As mentioned earlier, I really agree with a LOT of what the OP has stated, but didn't have time to make some clearer points on my thoughts.
I have to start by saying that Halo CE is pretty much my GOAT game, I've replayed that campaign a ridiculous amount of times, and it was my first console multiplayer fix both via LAN play and XBC. Halo CE to me IS 'Halo' and I've judged every game since against CE and they have all failed to dethrone it.
CE just got so many things right, and for some reason for me personally, even the 'flaws' (generally regarded as the Library, cookie cutter level design) in the game became things that I associated with 'Halo'. IMO Halo CE is just greater than the sum of it's parts.
When looking at the games in the series, I feel they can be judged/graded in 3 separate and distinct ways
1. Campaign (including co-op)
2. PVP Multiplayer
3. Overall Package (Forge, Firefight, Spartan Ops, Theatre etc)
The reason I feel these should be separated out is actually more to do with what each new game has introduced, and how this evolution has changed how I (and others) perceive each games value.
For me, as the years have gone by (I'm 41 now) I am less and less concerned with the PVP multiplayer side; i've never been particularly competetive (maybe except back when UT99 came out
) and back with Halo CE the multiplayer we had either via LAN or over XBC was nowhere near as erious as it has evolved to be these days, in fact I very quickly lost interest in PVP multiplayer in Halo 2, I didn't have enough time and wasn't competetive enough, would much rather play through the campaign co-op.
So for me the Campaign has always been the most important factor in Halo games, and I feel lucky enough to say that I've at least enjoyed and replayed ALL the Halo campaigns (actually still to replay Halo 5, but starting a co-op replay tonight!).
So yes, I will repeat -
ALL THE HALO CAMPAIGNS ARE AT LEAST GOOD! I find it hard to fathom where people say that ANY of the Halo campaigns are garbage, I've enjoyed them all, some more than others and some have bigger annoyances but they are all without exception decent, solid games.
Halo 2 is my least favourite campaign, and I also lost interest in Halo PVP multiplayer as well during Halo 2 (I can blame work circumstances and lack of time maybe on the multi side).
Halo 2 -
I can sum these up succintly - IMO Halo 2 is the Halo that didn't nail the 30 seconds of fun as much as the others, it broke the Weapons-Grenades-Melee triangle with dual wield, it introduced Brutes (IMO unequivocally the WORST enemies in ALL Halo games - yes including the Prometheans!), and the plot and narrative execution were poor at best, but I'd actually say I thought Bungie made a pigs ear of the story in Halo 2.
It also did not evoke that sense of 'Alien Wonder and Isolation' that Halo CE had in spades and to me is the hallmark and biggest theme in a Halo campaign (to me at least). I distinctly got the feeling in Halo 2 that a lot of stuff was experimental, and Bungie were throwing stuff at the wall to 'see what sticks'. It felt hugely different from CE to me, so much so there was a bit of dissonance.
Halo 3 - What a Package!
Halo 3 I think had a better campaign than Halo 2, but was quite uneven. It had really good high points - The Ark being the main one, but it also had the lowest of all the lows in Cortana. I played a good bit more multiplayer in Halo 3 because it seemed to me to be much more social and less competetive in nature with lots of game variants and content.
Halo 3 also introduced Campaign Scoring which I loved and got quite addicted to. add to that Forge and the huge amount of contente, and IMO Halo 3 is hard to beat as the best Overall Package, it had so much value.
ODST - Excellent Experiment
Next came Halo 3: ODST which for me is the biggest surprise in the whole series - whilst it was obvious Bungie were experimenting a LOT so much worked really well - the narrative execution was great, the noir feel and soundtrack were sublime, and the gameplay did not suffer for being an ODST and not a Spartan. It's currently my favourite campaign behind CE - I even didn't mind the Brutes much in ODST! The interesting thing is it still felt like Halo to me, even though it was very experimental. Like yet unlike!
Halo Reach - Ruh oh
I really did not like Reach when it came out, everything felt out of whack, the squad-based campaign just didn't grab me at all, and I really did not like the armour abilities direction. I think I really struggled first time round because of the dissonance between the Fall of Reach novel and the massive retcon that the game was. That said, after replaying recently I've warmed to it a bit, and actually quite enjoyed the campaign - it takes a bit of heating up, but the later missions are good, and the narrative execution is really good, even if I struggle to embrace the narrative vis a vis the book.
Halo 4 - A Mixed Bag
The first Halo game for 343i was quite frustrating for me, as they did a lot right with the campaign, but also got a lot wrong as well. I appreciate that a lot of the negativity for Halo 4 was around the multiplayer side, but as I didn't even touch the multiplayer in 4 I can't comment on that much.
Things I liked in the campaign - a LOT reminded me of CE - that feeling of 'Alien Wonder' I felt Halo 4 had it in abundance, Requiem, the Didact, Prometheans etc, I really enjoyed my first playthrough in the main, but a lot of the missteps were much more apparent in my 2nd (Legendary) playthrough:-
- Disappearing Weapons (limits of 360 tech?) this bugged me a lot
- More linear corridors and less open spaces; some of this actually reminded me of CE, but I think there was too much and nothing that really approached Silent Cartographer or Two Betrayals in size and scope.
- QTEs - only 2 but 2 too many (rectified in Halo 5 thankfully)
- Ham-fisted exposition and reliance on narrative devices outside the game (Waypoint)
- Promethean weapons really just were re-skinned UNSC weapons.
- Too much 'press this button' type missions; I think this is part of poor/lazy narrative excecution.
But for all these missteps I LOVED that 343 were actually tackling the Forerunners, and Didact and so forth. I think on the whole they had a thankless task to fill Bungie's shoes and were never going to please all the people all the time.
I still enjoyed Halo 4 campaign more than Halo 2 or Reach and probably on par with Halo 3.
I was PISSED tho at the removal of Campaign Scoring and Firefight. Spartan Ops was not a good replacement for Firefight.
Halo 5 - Moving in the Right Direction
First thing I can say about Halo 5 is that MOST of the little annoyances I had with Halo 4 campaign, 343i knocked out the park and addressed, no QTEs, no 'leave game and see video' type narrative exposition, no disappearing weapons, and much more organic mission and encounter design. So that is pretty damned good progress IMO. Again, I've not really touched the multiplayer side, but I did enjoy the couple of games I played - it FELT great. Going to be playing co-op tonight.
343 still could do a LOT better on the narrative execution side, whilst I don't have a problem with the overall plot in Halo 5 I think the way they executed it wasn't great. Some inexplicable stuff like Jul getting offed in the first mission, but then going on to have a big battle in Sanghelios; I'd love for someone at 343i to tell me their rationale behind that, and I will give so many rebuttals as to why it was a terrible decision. It really put me off the campaign very early, but fortunately a lot of other stuff pulled it back.
Swords of Sanghelios was a GREAT mission, loved it.
60FPS did make a huge difference, and Prometheans have been refined a LOT and offer much better feedback and are less spongy as a result. Knights are great to fight now. Hunters are fearsome in Halo 5, love that.
That said, I'm still not keen on 343is over-reliance on the 'waves of enemies' type encounter design, it does not feel very organic and reminds me a lot of very early FPS design. I think the Prometheans as enemies get as much of a bad rap due to the 'wave' encounters as much as anything else.
Additionally, I wasn't sold on the whole squad-based mechanic for a full campaign again. I missed the lone-wolf feel of Halo CE a good bit in Halo 5, and that was not just because of Osiris.
So I really enjoyed Halo 5, but still think 343 can do a LOT to improve things in Halo 6.
I should also note that I've yet to play through MCC (only bought a Xbone when Halo 5 came out), so I don't have any bias to or against 343 as a result of that (but the whole handling of it was shocking).
I will need to play through Halo 5 again on Legendary to really make things a fair comparison, and I really want to see some more content for people that are less competetive - give me Campaign Scoring, Firefight (or some other kind of PVE gametype) and give me some social playlists, especially directed at lone-wolf types who just want to jump in and play some free for all. I'd play much more Halo 5 multi if King of the Hill, Oddball and some of the other less 'serious' gametypes were reinstated.
What makes Halo a unique series IMO is the sheer diversity of what it means to different people - Halo 2 is my least favourite campaign, but it's probably some peoples favourite and thats fine, subjective tastes and all.
A lot of that comes from that fact that NONE of the Halo games have been a soulless retread, whether it's Bungie or 343 they have at least TRIED to grow and evolve and not just churn out the same game in different packaging and graphics, and I think thats a good thing, even if it pisses some people off.