GlassJaw
Hero
d4=1d3+1
d6=1d4+2
d8=2d3+2
d10=1d6+4
d12=2d4+4
I did something similar in a higher-power campaign:
Players could either take the mean+1 (3 for d4, 4 for d6, 5 for d8, 6 for d10, 7 for d12) or roll one lower die and add 2 (1d4+2 for d6, 1d6+2 for d8, etc). d4 had to roll normally.
For the current campaign I'm running (Dungeon Adventure Path), I'm keeping it simple: roll twice and take the highest. I like it and the players seem to as well.