To be honest, I'm not sure what you're complaining about. You have the exact same number of straight romances in DAI that you had in DAO and DA2. As for sexuality hamperng roleplay, I disagree. Dorian, whose sexuality is most prevalent to him and his storyline, has provided me with the opportunity to roleplay a somewhat sheltered Circle mage falling for a dashing Tevinter Altus, and all the political ramifications that entails.
If I were to play a Qunari and romance him, I would have the whole Tevinter-Qun animosity to play with.
If I were to play an elf? Elves are slaves in Tevinter, and also there's the business with Tevinter supposedly destroying the elven homeland and all that.
And a dwarf? Not a drop of magic in Cadash, something Dorian's family would disapprove of beyond the fact they're both men.
And of course, female Inquisitors get to play unrequited love or flirty BFFs with him.
That's just for Dorian. If you're going to sit there and claim having gay or lesbian characters is hurting your roleplaying options, maybe you should sit down and try engaging your imagination station.
Another Dorian fan! I LOVE that character. Inside of 5 minutes I loved him. Before I was done with his introductory quest he was my favorite companion.
My Dalish flirted with him shamelessly, even knowing the bad blood between Tevinter and elves and he certainly bantered along with her. Then the 'big reveal' from his personal quest happened and my Dalish just stood there flabbergasted....whhhat--preferring men, is that even a thing?--she was such a naive girl. She took it all in stride though and accepted it for what it was, harmless courtly flirtation (kind of like what happens with Teagan in Origins). She fell into Cullen's arms instead (yea I know, she just loved those shemlen men--I think it's the facial hair) and Dorian became one of her constant companions traveling everywhere with her. Along with Dorian, she picked Blackwall and Varric, who also possess hairy features in some manner, one on his face, the other on his chest, to travel with as she restored order to Southern Thedas.
There were options to flirt with Vivienne (she calls you 'charming' in an amused tone) and Cassandra, who ignores you if you're female. I am unsure who else you can just flirt with without them taking you up on it.
I was disappointed they weren't doing the "everyone for the PC" romances this time either, but considering the flak they took for the last game's LI's I can see why they did it this way. And if Dorian hadn't been gender locked I'd never have seen any of the other romances because he'd have been the one I'd pick every single time. I adore the character that much!