But it's not 3's and 4's lol. It's 2's and 3's like organized basketball always have been (since the 3 point line... still 2's before that).
Playing to 21 by 1's is no different than playing to 42 by 2's. The difference in your proposal is you're literally giving twice as many points for a shot that isn't that difficult (3 pointer).
I don't care about the gimmicky 4 pointer. If that starts getting used a lot that'd be a turn off. But just logically, I don't see any reason anyone should ever play 1's and 2's. I can see just 1's to 11 with ignoring of the 3 point line, but could never wrap my head around giving a 3 point shot more weight.