I think I will instead take away Powerful Build, as they are intended to be small, though definitely at the upper limit of it (the smallest ones would be 3 feet). I'll replace it with a different, unique ability.

I honestly hadn't yet had the time to check out the new races in the new E6 compendium you got, so I will, and see if I can make some better abilities for the humans and the Equrun dwarves. (Though culturally speaking, an Equrun dwarf without a pony would feel dishonoured anyway.)