For me it seems pretty obvious (based on public info) that the performance of TMG's WRC Yaris has been carefully evaluated and Toyota is not happy with it. It might be ok but their target in the future is of course to beat VW.

As Mirek pointed out TMG's recent projects have not been huge successes so perfectly right thing to do is to try something completely new. I have no contacts to TMG but for me it seems that it's a little bit old-school R&D unit full of middle-aged men (after F1 project was ended). Why else would they say publicly that now they want to buid a young team and attract new talents etc.

The one thing I fear is that Tommi sets up Toyota's operations to Finland even if it's not an optimal solution. The whole thing is perfectly doable from Finland but it's really a serious effort (+money) that is needed to attract the best engineering talents from other WRC (+F1 etc) teams from Central Europe.