It might not have a satisfactory ending, (wtf was that?), it might not be the anniversary show we all wanted (almost no return of old heisei actors, alternate universe), it might have the two best fanservice episodes ever (Kotaro Minami returned as Black and Black RX), it might be the first Kamen Rider to crossover with Super Sentai, but man, whatever Decade is, it was FUN.
Not fun in a sense that this was or was not a great series, but it's still fun. From it's first unveiling (wtf Pink) to its movie unveiling and news and bits, it was a great thing to look forward to. Kinda sad that this has ended.
Here's my opinion on every story arcs:
Episode 2 & 3 (Kuuga's World) : Almost felt like a Kuuga episode. Liked it very much.
Episode 4 & 5 (Kiva's World) : Since the actual Kiva was very underwhelming, I liked this one more than the real Kiva series. I can really felt that Kiva was a prince/king and almost everyone in his world recognizes him.
Episode 6 & 7 (Ryuki's World) : Don't like it. There's a huge inconsistency involving time traveling here, and the concept of Riders as lawyers didn't really click on me.
Episode 8 & 9 (Blade's World) : Again, one of the weaker worlds. Kamata was greatly underused as a villain.
Episode 10 & 11 (Faiz's World) : I don't know why, but I liked it. I felt a high school Faiz would work as a real series, or maybe because Faiz in this world was a classic incognito hero.
Episode 12 & 13 (Agito's World) : Liked the references to Kuuga, but not so much for the episodes. I liked how Gills actually became Agito though.
Episode 14 & 15 (Den-O's World) : Felt like a Den-O episode. Which means okay.
Episode 16 & 17 (Kabuto's World) : I like it, since it shows that Kabuto was still almost untouchable.
Episode 18 & 19 (Hibiki's World) : One of my favorite episodes, probably because of that epic Ongeki orchestra.
Episode 20 & 21 (Nega World) : Don't really like it, though there's a pointless Kurenai Otoya cameo and Complete form was a complete mess.
Episode 22 & 23 (Diend's World) : One of the weaker episodes, an underused potential villain, and it didn't really explain anything about Diend.
Episode 24 & 25 (Shinkenger's World) : Crazy mindless fun with the Shinkenger guys! I liked it.
Episode 26 & 27 (RX and Black's World) : Best fanservice ever.
Episode 28 & 29 (Amazon's World) : Pretty weak episode and pretty weak Amazon. Meh. Great villain design though.
Episode 30 & 31 (Rider War World, finale) : Goddamit that wasn't even a finale.
And that's it!
I don't have any huge hopes for Double (from the promos, it looks like it will be as light-hearted as Den-O which wasn't my cup of tea), but the prospect of a new writer intrigues me. I'll watch all of it, I think, as was all the heisei riders.
. He's one of the best things about this show, I swear. They really needed a better actor for Amazon. I guess Decade using the Final Attack Ride: Amazon card proves that Tsukasa can use Showa cards. Looks like Kaito was just trolling him when he said Decade couldn't use the Black card, proving that he is indeed a douche. Also, lol at Apollo Geist just saying "Fuck it" and leaving Jyumenki to get triple teamed. 
