I highly disagree. There will never be any such thing as a true specialized class unless we implement actual "classes". As an archer I don't need a single wpf in 2h or polearms to melee. Not a single point, and I can melee just fine. You know this to be true as well. Do we ban archers from picking up melee weapons at all?
As a 2her/polearmer I can pick up an xbow without a single wpf in it and have ranged capability. Not a single point and I can shoot people fairly reliably. Do we ban them from picking up an xbow at all?
As a thrower, I don't need to put a single wpf into throwing since it's a crapshoot anyways. Currently I have 100 wpf in throwing on my 2her that feels wasted anyways, as I have a 1her with throwing but only 1 wpf. Same PT level (5) and they both are just about as (in)accurate as each other.
So how would you propose we "balance" this? I have a 1her/polearm character with 130 wpf/100 wpf currently and it doesn't seem like anyone has a complaint about double melee hybrids at all, just anyone that's a ranged/melee hybrid. So what is the proposal to prevent this, because under your system I'll just make hybrids where I can use one without any wpf at all and still do well (an archer/2her, or a 2h/pole + xbow, or a thrower with 1wpf and the rest of the wpf into melee).
I really don't see how this would create more diversity at all, unless the overall point is to reduce the ranged in the game in which case I still have to ask: Why don't we just get rid of ranged altogether? Seems the only thing to do is make ranged more and more worthless until only an idiot would choose to be one because of how nerfed/ineffective it is so why beat around the bush and even have it as an option?
When people say jack of all trades, master of none what they really seem to mean is "Gimp at everything." If that's the case, why bother? Currently specialists DO have a mathmatical game advantage over real hybrids. Sorry, your having 150+ wpf and 3+ extra stat points makes a BIG difference mechanics wise over my hybrid who sacrifices those levels of stats in order to be versatile. If I beat you, it's not because the mechanics are flawed, but because I out played you. I know that no one likes to hear that, but it's true. Just like any archer that has 1 wpf and picks up a katana/longsword/whatever and kills you in melee. The mechanics didn't fail, you did.
TLDR: If you change WPF we hybrid players will simply go back to making builds that require no WPF to hybrid (Archer + 2h/pole, 2h/pole + xbow, 1h/shield + xbow, Thrower with all WPF in melee weapon and simply rely on PT level for accuracy). Effectively pre-patch hybrids which were in reality pure builds exploiting mechanics rather than building a real hybrid like currently.