Making them some kind of smiths and miners like dwarves could be a really cool idea.
In d20, even horses and ogres get a natural armor bonus, so I think giving one to turians is quite justified. This would be swords and arrows, not hypersonic tungsten particles fired by mass accelerators.
Making Krogans exactly as described would probably demand a huge Level Adjustment and I would like to avoid that. Though in their case, racial paragon levels might be neccessary.