This is the plain raw truth. Funnily almost all of Yoshida's reputation was built from Tanaka's unfinished work. Hamlet, NMs, materia, primals, even companies both grand and free were all planned since the beginning and well before the team shift, Yoshida simply just gave the go to the team to finish what they started while he worked on 2.0 on the side and put most of his efforts into it. He just gave them the time Wada didn't give the original team. Almost all of the content from 1.0 after the team shift was content that was already in different stages of development but far enough that it could be finished and implemented along the way. A lot of it was in the game pretty much since launch like data mining proved, such as dungeons like Aurum Vale. Only a handful of Yoshida's ideas were added into 1.0 like jobs and the ability simplification.

Even funnier is how almost all of those unfinished concepts and various progression options that slowly got finished entirely disappeared in 2.0 such as Skirmish, Hamlet, Beastmen Camp NMs, Faction Leves and Chocobo Caravans, simply because they weren't part of Yoshida's vision, they were from Tanaka's. 2.0 effectively launched with less endgame content than the game had built up to 1.23. This is of course regardless of how "fun" that content actually was and how much of an impact 1.0's engine had on it, since that content could have been updated for the new engine and new gameplay mechanics. Yet 2 years later those different mechanics still haven't been reimplemented and we're still stuck with the exact same 2-3 endgame dungeons > single 4 boss raid > single 24 man raid pattern.

2.0 was of course all Yoshida, concept and mechanics wise, aside from the 1.0 assets they reused to save on costs. It's obvious just how much the relaunch took and still takes its fair share from WoW and other themepark MMOs, since they themselves admitted were looking at various MMOs around 2.0s announcement. They took a lot from other games they perceived as successful, especially Rift, since the game shares quite a lot of ideas from it, and being the only sub based WoW clone that was doing relatively ok at least in 2010-2011.