Fanservice aside, you gotta admit, Yoko in Gurren Lagaan was still rather badass in her
Big Damn Heroes introduction at the beginning of the series, as well as her return after the time skip.
Giant mecha threatens underground city, Kamina being the manly man he is and Simon wanting him to get away before he gets himself killed, and just before Kamina actually does anything *BANG BANG BANG* and she's swinging down ala death from above. If anything, the weapon she used, and her
MacGuyvering of it drew my attention more than her body.
Some moments, the times of awesomeness outshine any fanservice shown. I think Gurren Lagaan was a good test of that.
I don't mind fanservice, but only if it's used appropriately. If it's just plain gratuitous fanservice (like a beach or spa episode or something), then at least provide a sort of filler that catches us up on the important things, or allow us to know what's ahead so story-wise, the episode isn't a total loss. I mean, if fanservice and likewise is the ONLY thing on my mind, I'll go looking for hentai instead where fanservice IS the point.
EDIT:
In the same vein,
The final episodes of the series are so awesome, you completely forget, or are unaware of Nia's bareness throughout. Goes to show that awesomeness CAN outshine fanservice.