XIII sold well enough but spinning it off into now two sequels probably doesn't match the market that well either.
I agree, but I think that's partly because they poisoned the well with the first game.
AC:B and AC:R performed much, much better than FFXIII-2 did both in relative and absolute terms despite being similar sequels in concept, but I would propose that's because the general audience actually really liked Assassin's Creed 2.
While the game in and of itself was a financial success, its lasting impression was problematic. The game's reception along with their inability to change the design enough to win people back over speaks to direction problems at the company, and their inability to release a new, highly different product speaks to production problems.
Last Remnant was an unfortunate mess caused by lack of experience/documentation with UE3 but the game itself is decent. Crystal Bearers had terrible timing and XIV was a mess during development. Tanaka apparently wanted to change things other staff were doing but felt he would be too pushy in doing so, so he left it as it was... and we all saw the result.
I feel it's notable though that the games received Metacritic ratings of 66, 66, and 49 respectively, and were all large commercial failures that also had seemingly poor production schedules.
When you're failing on the commercial, critical, and development fronts, I could see why they're losing confidence in their own ability.
The biggest problem is that I believe I also just listed all four internally developed Square Enix consoles games released in the West this generation sans Final Fantasy XIII-2.
As it stands today, they have zero consoles games they can point at in the international markets and say "This was an unqualified success." That's got to have a tremendous impact on confidence and morale for a formerly leading edge studio that is sitting in year seven of this generation.
I would propose they're out fishing for feedback so significantly because they honestly don't know what they're doing wrong or where they should go, especially in a market that's rewarding maybe 10 console titles a year at this point at the level they would want mainline Final Fantasy to sell, and they know that most (and often all) of those receive extensive user testing.
That said, most of the user testing is probably handled a lot better than Square Enix is doing judging by the result of Final Fantasy XIII-2, but I can see on paper why they want to try.