I can understand the one i bolded but the rest? So what if one of the devs like a character or even got a DLC? I think the reason why Liara got a DLC is because she wasn't a squadmate (neither are Ash and Kaidan, they should've had a DLC too) and she had her own problem with the SB and since she happened to be the one who 'saves' Shep's body.... with Miranda, although she gets hate for other lame reasons and not because she helped 'fixing' Shep.
LIke i said, i never understood the Liara hate.
I want to clarify that this is not my point of view. I don't have a problem with Liara. I don't like much the fact that the friendship is forced, but that's not her fault (and I'd go for the friendship in my canon anyway).
I don't think that people have a problem with her having a dlc in itself; the problem is more related to the fact that the VS didn't get one, and this is related to the fact that she's Walters (the lead writer) favorite character, because (some) people think she got a better treatment because of that. Which is the reason why some people dislike Garrus and Tali, becuase they got a better treatment than the other ME2 squadmates.