That was my take as well. And while I might have a few minor gripes, I think she was much better written in ME3 than in ME1.
For clarificiation, I liked her plenty in ME1. But yes, there is no doubt, I liked ME1 Liara. I love ME3 Liara, since she is so much better developed and fleshed out character 
As you say, Liara is the one you chose, so of course her high amount of content will satisfy you. The only drawback I see for a Liara fan is the dual relationship Bioware tried to stick her into, in which she apparently failed at both. For me personally, I don't hate her. She is a character that I didn't see having a strong case to be in combat in the first game (on the Normandy was fine as she was the Prothean "expert"), and my main gripe (same as I have with Garrus) is the fact that the is assumed to be my bestest friend. I'm happy that you're happy with your experience, but I would rather Bioware just go ahead and state that "This is your LI" rather than underhandedly canonize one through sheer content/plot relevance.
I don't think she failed. Yes, there is little difference between her friendship and romance paths, but the differences are there, subtle as they may be. I attribute that to Liara herself. She cares a great deal about Commander, be it as a friend or a lover. Could they(Bioware) do it better? Probably, but given everything else that's wrong with this game, this is a minor gripe at best. Do I believe she is in love with Shepard no matter what? That is one possibility, though I don't subscribe to it. But she obviously does think a lot of him/her and is not afraid of showing it. It really is fridge logic, when you think about it.
Which brings us to your other point, of her being your assumed friend. I think this is one the things that has been canonized, whether you agree with it or not. Liara, Garrus, Tali(possibly Wrex and VS) are supposed to be Shepard's friends. They have been with him/her for longer than anybody else and the third game goes to some lenght to show that. And it's fine with me, but I can see how some people would take issues with that.
The games supposedly don't subscribe to any canon, but I really believe this to be the case.
No shi* she has the most content.haters gonna hate is so f***ing corny ,YOLO fuc* it
Tell me how you really feel 