MEA would you like to play as another species?

Nope.

"Good writing" sounds nice, but I'd be curious about how much interest a krogan-only PC would actually get in the real world. It's a fair bet that such a setup would turn a good number of people off. For myself, I know outright I'd never buy that game, because aside from having zero interest in playing 30+ hours of any of the ancient milky way wars, I don't think I'd care to hear hours upon hours of nothing but gruff krogan voices and looking at a bunch of bat-faced dinosaurs with shotguns. 

Yeah, that's how I'd see it playing out as well.

If we could play as an asari, literally everyone becomes a romance option.

Very true, may solve a lot of the issues on the forums at the moment 

No more than a human female. Straight women and gay men wouldn't suddenly become options for asari. 

I wouldn't be opposed to an eventual entry into the Mass Effect series where other races were playable. The big however is Bioware would need to devote a lot of resources to increasing the amount of models and customization option for other races and deciding which races get that treatment. I can imagine a good portion of the fanbase will riot if Turians and/or Quarians are not playable due to the popularity surrounding them.

I do think Bioware should bring back control over our companions in combat. We seem to lose a little more each game entry in terms of customizing and directing them. ME:A2 would benefit from the ability to switch between party members with us, like we could in KOTOR or Dragon Age: Origins, and I'd argue that implementing a tactics system like we had in Origins to specify companion behavior based on certain conditions would be very useful for us tactical types that want to play through Insanity on a regular basis.

I've said in the past that turians and asari are the safest bets for race options. The problem with adding any more on top of that really comes down to the number of different distinct voices required each added species, aside from issues with animating in cutscenes with characters that can have significant size differences. Quarians and turians could potentially share the voices across genders, though some fans would undoubtedly bitch at the lack of the signature accent (just like how DAI's elf does not share the same accent with other Dalish but instead talks like a shem). 

Beyond that, anything more would put the voice count at 6, which is quite a lot for a game with a lot of spoken line options.