>>10244398>>10244547I've don't an MOC of a centaur mech, and I can tell you that they used that static part for stability reasons. There's no way they could have efficiently done a fully articulated centaur without blowing a ton of the budget on specific pieces to make the front legs both stable and articulated. And even still, based on my own mech and researching how other people have accomplished it, the stability still wouldn't meet Lego standards.
Tldr
That's literally the best they could do with that figures design and budget.