Yeah, I know, there are a million of these things, (which is really a testament to how absolutely terrible Oblivion's leveling system is.) but none of them do exactly what I want them to, so I decided to make my own.

0 skill ups works as it always has.
1-2 skill ups nets you a +3 modifier.
3-4 skill ups nets you a +4 modifier.
5+ skill ups nets you a +5 modifier.

This makes it far less tedious to get good modifiers but still lets you play the system a bit to get the best modifiers.