Would be easy to cap attributes to 1 point per level. Then everyone can invest in two things.
You can already invest in 2 things anyway if you want. That is what a hybrid is. Your suggestion is to force everyone to make everything a hybrid.
You can "beat" everything in this game (up until now) without putting a single point in anything after what you start with. A few 5% here or there is nothing.
If I want to put all my points into FIN as an archer then I should be able to. Why should I put a single point in anything else? That is the point of such a game is it not?
Play hybrid if you want (it works for me). Or don't.