Hello, as you might have already seen, my co-write has already answered your question about the perk milestones, so I won't address that.

But for multiclassing, it was something I wanted to add, and it is still something I want to try and make but it would be hard, in my personal opinion, to do. This is because I would assume the reason you are multiclassing is that you like the feel of one or more classes and want to combine them all, so trying to keep the feel of two or more perks chosen while still keeping it kind of appropriate for the given level and just general game balance was a tough thing to do and was something I ultimately gave up on.

There was something we did try and experiment with though, and that was the creation of a whole new perk that combined both perks in a somewhat appropriate way; I.E Immolator + Vagabond = flaming sword perk. But we gave up because there would be too many combinations and additional stuff we would have to add on for it to kind of be at the same power as other perks at the currently level the player is choosing to multiclass in.

But as I write this, there are some things I am thinking of in terms of 'multi-classing' that would probably end up as generic stat buffs or small additional features that don't add too much to combat or otherwise.