No Ability Scores, just Modifiers

[Nonlethal Force]

It's slightly more than usual, but really not that bad. The 4th modifier won't be until very high levels, so you're talking about archmages and hierophant priests. I've seen suggestions (Unearthed Arcana or the Advanced Gamemasters Guide) for a feat OR an ability boost every level. That's a little over the top for my taste.

Yes, that's true. Of course, I also am a proponent of as long as the same conditions are met by the BBEGs as PCs, then it should maintain a semblance of balance. So, as long as the opponents of the party are generated using the same method, it should actually work against the PCs since there is far more of them than PCs. But yeah, every level is abit over the top!

 

[Warbringer]

I do the same in my TrueD+D campaign.

To limit abuste (ie +7 in one stat), the limit is the top 3 stats can't be separated by more than +1 each step...

e.g. +3, +2, +1 .... +4,+3,+2 (though a couple of -ve s are needed)

This is before race modifiers... Works OK