Now this sounds like a drastic suggestion, and it is.
It is also inspired by Pillars of eternity and their character creation where abilities are determined at 1st level and only can be increased by magic effect after(and some rest bonuses).
By removing GIANT boosts in power at lvls 5,10,15,20 and concentrating it all at 1st level, it is easier to balance 1st level and all after.
By removing ancestry(racial) and background bonuses, we eliminate forced stereotypes for class/race combos.
Other racial features could help some class more than other, but abilities are where impact is the hardest.
Now:
we start with all abilities at 8.
People wan't some penalties, we should provide them.
Every character would get 33 pts to improve their abilities.
Cost would be
8, 0pts
10, 1pt
12, 2pts
14, 3pts
16, 4pts
18, 6pts
20, 8pts
22, 11pts
that could give arrays:
22,22,22,8,8,8
or: 20,20,18,16,16,16
or: 18,18,18,18,18,16
or anything in-between.
Would this make 1st level characters more powerful?
Yes, but it would avoid "super levels" later on as there it would not be any huge ability boosts.
it also makes low power campaigns easier to make. Just lower the points in ability pool.
There's definitely a certain appeal to locking attributes (which are labelled abilities in game) in at level one and keeping progression focused on abilities/items (which are labelled powers, feats, etc in game). It's not really necessary but I wouldn't be opposed.