Squaresoft was better managed than Square Enix.
Yes, it has nothing to do with the fact that development of games has become about a billion times more demanding than even their biggest PS1 games and even mid-budget games aren't exactly small affairs anymore. Sadly the days of any publisher being able to keep up with the insane release schedules from their SNES/PS1 days are long over. While you can argue they have done some poor decisions (releasing XIV 1.0 in the first place and then fixing it at the expense of pretty much everything else, pumping out FFXIII games despite their relatively poor reception), not being able to keep up with their crazy game development pace of their Squresoft days isn't all about mismanagement. Whereas they could go from conceptualizing into having a team of 30-50 develop Vagrant Story all within a couple of years, if they wanted to develop something relatively similar on PS4, they'd easily have to double or triple the team size and/or add a year of development time, if they want to make something that looks like a PS4 game and would have a tiny chance of success (most people would dismiss it in a second if it looked like a mid budget PS2 game in 1080p).
The only publishers that are even near to their old release output (as far as quantity goes, not necessarily quality) are the kind that have grown a lot since then (and even they are quite far from those "golden days"), but Square Enix doesn't quite have the luxury to be able to do so because JRPGs aren't any kind of gold mine for publishers nowadays.
SE job posting looking for someone working on online game(s) related to FFXV:
https://js01.jposting.net/square-enix/u/creator/job.phtml?job_code=450
Seperate online component for FFXV or an eventual FFXV-2 with a bigger emphasis on online/co-op?
Haven't they confirmed a separate mobile and/or Vita companion app? Could just have something to do with that, considering they have scrapped the idea of several playable characters (if a coop mode had you play with the other characters, why wouldn't the main single player game?)
Yoshi-P is already calling 2015 the year of FF14 again so it seems like Heavensward + patches will carry them for quite a bit once again. They didn't have much either on the JP side this year aside from HD ports and a couple handheld games so another year of the same wouldn't be anything different.
If XV were out next year they would have at least put a year listing in the trailers. So far we've had none of that coupled with Tabata saying it's further out than you think... it's pretty clear the game is not out next year or even early 2016.
I'd say the fact that the past couple of years have been weaker would be a reason to try to bring FFXV out by the end of March 2016. After already having a pretty weak past two years, will they want to have a third weak one? At least before they had XIV ARR's development as an excuse for having more silent years in terms of releases, but that excuse is long gone.
And them not announcing a release year yet is not all that damning. They didn't commit to a Winter 2009 release for FFXIII until April 2009. If we don't have a release quarter for Q1 2016 at E3 2015 at latest, then I'll believe FFXV will probably not arrive by the end of their next fiscal year. Before that they might just want to until they are more certain they can deliver on their promise or even have an exact date and I'll remain hopeful. Tabata's "it will be released a little later than people think" might just be about them not quite following a similar release schedule as FFXIII did after the demo (demo in April 2009 -> release 8 months later), not that it's still 2 years away from release.
http://kotaku.com/5274775/final-fantasy-xiii-still-on-track-for-winter-2009-release
You're forgetting they've already said they are planning to announce titles from SE Japan in 2015 though. And with that, Heavensward will receive big support and continue to well into the year. They already have a number of titles spread out to release from all branches.
XV is not going to be ready by March.
Announcing games is different from releasing them. What games could they realistically announce to fill rest of their fiscal year?
Dream Drop Distance HD is probable
Ito was only coming up with ideas for his next project around the time they were finishing A Realm Reborn in Q3 2013, so unless it's a mobile game, I doubt it'll be released until mid 2016 at earliest, probably a lot later if it's (hopefully) a bigger scale console release
Toriyama finished his last game only a year ago, so while he'll possibly announce his next game in 2015, I doubt it'll release before we are well into 2016 (at earliest), could even be a 2017 title if it's for consoles.
SaGa we already know is coming in 2015
Seiken Densetsu's 25th anniversary is in 2016 so they are probably not going to release anything bigger Mana related in 2015.
Osaka Team is developing KHIII for late 2016 or beyond release
DQXI is under development but we have no idea how far along it is. Could be anywhere from mid 2016 to late 2017 or beyond, but doubtful it's a 2015 release when they haven't even shown a glimpse of it so far.
The new console RPG studio they set up? Probably still building up the team and in the early phases of the project(s) they are going to develop
Collaborations?
Final Fantasy Explorers was just released so that team will take at least 2+ years from now to release their new game, even if it's "just" a portable game
Silicon Studios is finishing Bravely Second so obviously they aren't going to release anything to fill out the rest of the next fiscal year
Dragon Quest Heroes will be out in a couple of months, so there's probably nothing else from Tecmo Koei x Square Enix for Q2 2015-Q1 2016
indiezero is finishing up Theatrhythm: Dragon Quest
Matrix Software seems to have been delegated to mobile ports and even if their next game is not a mobile game it will probably be a smaller scale release and release it in 2016.
Tri-Ace? Will Square Enix work with them ever again as anything other than temporary help with getting SQEX IPs out?
Square Enix has a lot cooking behind the scenes but I believe that due to XIV ARR being such a resource hog and putting the whole company in such disarray until Q3 2013, most of the stuff that they have started developing after ARR's release probably won't start materializing until 2016.