Very true about cute girls in power armor! I never minded the whole open power armor thing found in anime such as Infinite Stratos, Undefeated Bahamut Chronicle, Hyper Dimension Neptunia somewhat, etc but on the flip note full on mecha from the likes of Cross Ange, Muv Luv Alternative/Schwartzmarken, or Tenchi Muyo War on Geminar are all pretty amazing as well. I think a lot of peoples problem with the Omniframe design is its kind of caught between both worlds. It looks much more mecha which are almost universally closed cockpit and much less like power armor/frames which people tend to not care as much if they are open to the pilot.
Aside from that the only real chainsaw weaponry I am familiar with is from the Warhammer 40K which has its own style of art for sure but that artist above does a great job making chainsaw weapons looks sleek.