I dunno, I see people who say they have 30ish str and 3 agi, and they run faster than they should.
If they buffed ironflesh, it would be nice.
Kesh already suggested increasing weight's speed reduction effects. Right now in heavy armor you have almost no speed penalty (although shields seem to give quite a bit, confusing.)
So, yeah. The tin cans should get slower at running
and IF def needs a buff, i think +3 HP rather than +2 is perfect.