The only major problem I see with Git is that it's just a pain if you're working in a gigantic monorepo.

Outside of this, I think it's achieved it's ultimate form and tradeoffs for what it was originally intended to do - and the majority of projects fall under that category, meaning that while Git can be improved, but it doesn't need to 'change' architecturally or philosophically to accommodate other things.

Separate version control software can be designed for solving a specific problem - but I don't think Git should need to evolve beyond the problems it's designed to take on.