Omniboost

[Angelalex242]

How would it change gameplay balance if, instead of raising one stat every 4 levels, you got to raise all 6 of them?

I just thought it'd be nice to do something for those poor innocent MAD classes, who need so much to be truly strong.

[RedMage125]

Or do what 4e did, you get to boost 2 stats.

[Flickerdart]

Giving a +2 modifier to a bunch of things isn't going to upset the existing balance very much. Everyone that sucks will still suck.

[ace rooster]

I would guess not a huge amount of balance impact, but it would remove PC distinctiveness. Every PC would be walking around with fairly similar ability scores that are all decent. It would affect the casters slightly less than mundanes, but giving every level 8 character an extra hit point and skill point will benefit the d4 hit dice characters significantly. On the other hand giving the dex 13 fighter in full plate an extra point in dex is a bit of a waste. I also don't like the flavour of the wizard getting stronger as fast as mundane combatants.
If balance is the aim then some sort of system of points for buying ability score boosts based on class could work. I kind of like the idea of a monk gradually turning into some sort of paragon rather than directly focusing on anything. You could modify the cost of various ability boosts based on race as well, making racial choice more important.
Just a few thoughts. I like the idea though.

[Elkad]

I give my players a +1 to their lowest stat (random if tied) to go along with the one they get to choose to apply.

Doesn't make them all the same, but it does give them a bit extra.

[Angelalex242]

I don't think the primary casters get as much out of their secondary stats as melee does. The wizard barely notices his strength and charisma, he only vaguely notices wisdom, pays minor interest to dex and con, and int is all he really cares about.

The monk, however, can make use of everything but charisma. Paladins can make use of everything. Dex? That's just an excuse to buy Mithril Full Plate instead of Adamant Full Plate. Rangers use everything too, thanks to wild empathy.