http://masseffect.wi...arians:_Economy
Quarians are frequently hired in Citadel space for mining, engineering and programming jobs. Part of the hatred for them is because they will work skilled labor positions for lower pay and "take" jobs. Propaganda campaigns and lobbyists portraying them as criminals, and paid for by mining corporations who rival them for resources don't help this perception. They've even gone so far as to try to use false flag attacks to frame the quarians.
http://masseffect.wi...#11.2F27.2F2010
It is notable that there was an asari diplomat who dissented, so the racism seemingly isn't universal. I'd imagine that it wouldn't be widespread among the intelligentsia of Citadel space (because smart/ well educated people tend to be less inclined towards racism), and would be more of a populist opinion among the middle and lower classes, maybe with a few political demagogues stirring the pot when it suits them.
Examples of quarians hired by Citadel species include Tali (hired by Udina to work as an engineer on the Normandy SR-1 regardless of Shepard's opinion on the matter), the quarians who worked on the asteroid station in BDTS (if you take the quarian armor as your reward from Atwell after defeating Balak, he mentions that it is from one among several that they hired to work on the station, along with a compliment that they "knew their stuff"), and the one that the asari forced into debt slavery as an AI programmer on Illium that you can get contracted to Synthetic Insights. Further, every single adult quarian has experience working in either Citadel or Terminus space on their Pilgrimage. That there is racism doesn't seem to mean that finding work is impossible.
By contrast, I never really got the impression that krogan were used as anything other than mercenaries, which really isn't the most useful profession unless you just don't have a standing army or private security contractors. Another stepping block to this project is that they had no diplomatic relations with the Council (partially due to lacking a central government). The quarians at least had that (there are treaties between the Admiralty/Conclave and the Council, even if they are not allies), so there is at least an official mechanism to include quarians if both parties saw it as desirable. I don't see how one could suddenly start hiring krogan mercs without notice, and that's before you consider the fact that krogan have both much higher nutritional requirements and need to be sedated to be transported if there are many of them (mentioned by EDI that otherwise they tend fight each other in enclosed spaces like starships).
However, krogan are in the game, so I doubt that there are any practical considerations at play that would trump their popularity. Whether or not quarians or any other non-Council species are included will be down to a popularity contest, and by that logic I don't think quarians will be included. As said, the general fanbase not only doesn't like them, but actively dislikes them. Only around 1/4 of players chose the quarians at Rannoch, and it was the least popular of the 3 choices by a significant margin. For comparison 92% of players cured the krogan's genophage, showcasing their popularity. Along with the asari, they're the one species that is pretty much synonymous with Mass Effect in the public eye. The quarians aren't. The geth sort of are, so there's a chance they'll be around, which would require mentioning the quarians, but I doubt they'll be there either with Biower wanting to wash their hands of the setting they wrecked in ME3. Both can be deleted with little protest, which would conveniently get rid of their.......uncomfortable "organics v synthetics" subplot too, so that's the most likely scenario IMO.
The last paragraph is exactly my thinking. I completely agree with Killroy that the smartest design idea would be to allow for the possibility of any of the MW species to turn up, but what I think the best idea is and what the Devs think they should do are concepts that rarely align. I'm trying to guess at what they'll consider practical, and the low-ish popularly of Quarians with the fan base gives me pause.
It feels really weird to be faced with so many arguments for why Quarians should be in ME:A, when I thought I already joined that choir some time ago.