I defended Tabata in this thread and have a lot of respect for how much of himself he has poured into FFXV and created a successful (liked by many) game. But your comparison there is inaccurate.
This is a more accurate comparison:
Things Tabata accomplished since taking over FFXV and BD2. (2013-2017)
* Released Episode Duscae in 2015 with Type-0 and then later Platinum Demo. Both separate from main game.
* Released a remaster for FF Type-0 HD in collaboration with Hexa Drive.
* Completed work on their own flagship internal game engine: Luminous Engine.
* Released Kingsglaive: FFXV CG movie prequel. Tabata was one of four co-producers
* Released Brotherhood: FFXV anime tie-in. Tabata was an executive producer and helped Oofuji conceive of the idea at the start
* Released Final Fantasy XV after two month delay. Released Two Story DLCs for it. Released monthly content updates for the game, often featuring free DLC.
* Started work on their own new IP within BD2 utilizing cutting edge next gen tech from Luminous Engine. From what Tabata said to DualShockers earlier this year (said his Business Division 2 staff were on XV projects or moved to other business divisions) barely anyone is working on this yet. From the IGN interview this thread is based on it seems like real work wont start on it until 2018.
* Producing Type-0 Online, announced PC version still unreleased
* Worked on a highly competent port of FFXV for PC with mod support, next generation visuals and features. *This port is still months from releasing so its too early to say its "highly competent" even if it looks good in trailers/sounds good on paper
* Worked on a FFXV standalone expansion for PSVR. His role on this is in its final form is unknown from what I can see
* Working on FFXV: Pocket Edition, yet to be released. A full story game from FFXV for mobile.
* Released two mobile games based on FFXV universe. Tabata didnt work on these much at all, if he did he was very very loosely involved as XV was his focus
* Showed a 2 and a half-3 minute tech demo based on 'Witch' concept utilizing cutting edge next generation tech from their Luminous Engine.
Things Nomura accomplished since leaving FFXV (2013-2017)
* Oversaw the development of and drew art for KH HD 2.5 on PS3
* Quite involved with Dissidia Final Fantasy (arcade), acting as creative producer being involved with many aspects of the game as seen by him participating in every Dissidia livestream helping elaborate/comment on most aspects of the game discussed/changed/added, designing every single character added + already implemented and talking about it in interviews
* Directed, wrote the scenario/base plot (possibly did more than this) for Kingdom Hearts X (PC browser, not the same as KHUX)
* Took charge of FFVII: Remake as director. Still TBA despite original announcement in 2015.
* Creative producer, concept design along with character design for Final Fantasy Record Keeper
* Directed, co-writes the scenario, writes the base plot and oversaw game systems for Kingdom Hearts Unchained (Union) X (if you dont believe he is this involved with KHUX or previously with KHX see this recent quote from an interview with Dengeki:
* Re-released Kingdom Hearts remasters for PS4 (oversaw this, as evidenced by how he spoke about how they were making trophies easier etc in interviews before release like this:
"We are currently tweaking the hurdles to be a little lower. That's not to say that the games will be exactly the same aside from trophies; we're making fine changes.").
* Released Kingdom Hearts DDD remaster and tried to catch up fans on some stuff from Chi they probably missed with a cinematic movie (Unchained).
* Released a demo for KH3 featuring Aqua.
* Creative producer on and designed the non-chibi characters of World of Final Fantasy, worked a lot to get Disney's approval for putting Sora into World of FF
* Confirmed Kingdom Hearts 3 is out in 2018. Didn't confirm any release date, Tabata confirmed XV for 2016 in the summer of the year before with no release date also, so that doesnt discredit Nomura in this comparison. Game was announced in 2013 with FFXV but then had to change engine due to the FFXV team understandably needing to merge with the Luminous team, setting back the game but it was out of Nomuras control since he was off XV at that point when the XV and Luminous teams merged.
* Creative producer on the Dissidia FF PS4 version, there are some differences between arcade and console and as said in a recent Dengeki interview Nomura worked with its director Kujiraoka on how to approach the PS4 release
* Tonnes of character design roles for various projects, some for high profile projects like Smash Bros for Wii U and 3DS and Xenoblade Chronicles 2
* Dropped CyberConnect2 as co-developer for FFVII: Remake, but it seems they are keeping a lot of of CyberConnect2s work since Nomura confirmed FFVIIRs cutscenes and other areas are further along than they are for KH3 (and KH3s cutscenes would be far along at this point since its scheduled for 2018).
They've both accomplished and are accomplishing a lot. Shouldn't have to put down one or the other whenever discussing either one.