What cruel person put Leliana and Liara in the same bracket?? :-o Had to pick Liara because of how the romance developed across all three games, but it broke my poor heart a bit.
As for improvements...I'm not sure. I'm a fan of romance as an option in RPGs. BioWare does it pretty well, if not perfectly (but perfect isn't even possible, is it?). Inquisition improved on their previous form. It was never romance so much as their sex scenes. My Warden loved Leliana to bits, but the love scene was fairly cringe-tastic. The ME1 scene with Liara was rather trippy, but the one in ME3 was better. Hawke and the Inquisitor didn't get sexy scenes due to romancing Isabela and Josephine respectively. Actually I liked the way the Josephine one played out - I heard lots of ranting that there was no sex scene, but it kind of made sense given the gentle courtship thing going on with her. She's a lady, don't you know... 
Despite being gay myself, I'm glad they did away with the default bisexuality of the LIs that we had in DA2. Makes it more realistic. My Warden had a thing for Morrigan, but it just wasn't going to happen. Same with the Inquisitor and Cassandra. I think having a range of options in that way is better. Of course, it inevitably leads to all out war in the fandom, but hey, what doesn't... 
I guess romance plots are a hard thing to get right in games. I think BioWare do a good job overall though.