Ehnh. I don't think more levels needed going to the place to do the Wrex thing. For one thing, you get the quest even if he talks about it. There are some random stuff--ruins of a dead guy, for instance, or Prothean artifacts--that are pretty cool, but honestly, if all planets had minerals to be mined (because all planets would), and only some had those artifacts, I'd be happy.
It'd feel FAKE to go to those planets and always have something interesting to find. It'd feel way more immersive to go and be like "oh, well, we found some minerals, I guess." It would also make finding those unique things way more special.
Mako was FUN, but the MAPS were problematic. It felt like they made one heightmap, didn't really bother to make sure it was drivable, and were like "kk, cool, we're done." What they needed were better maps.
And I think you're right. Flora and Fauna would be good, instead of "oh, every planet we reach has the same geth/pirates/that one big alien monster on it." To a degree, they did. Remember the random monkey village, or the alien cow that stole your money? So great. But... plants were pretty uncommon.
I think better planets to land on and explore would be good, but always having something to find, some quest tied into things... that's just bad design.
