Frankly, with sex being something not talked about enough IRL (which harms relationships), I consider it a good thing to be more open and upfront about it.
Also, there's a difference between sleeping with you and "romance". Lae'zal makes this VERY clear. You're her pleasure toy, not her lover. She's one of those people that will use you BEFORE getting close to you. It's not too different then drow. You see a bit of that in BG2. Just not with the companions themselves.
If anything they need to dial the romance up in places. Have REAL talks about knowing each other. We get a good bit of that with Shadowheart. But you don't always need someones life story. Depends on selfish/selfless someone is from the start. If it leans more towards selfish, more talks. If it leans more towards selfless, then the talks involved would consist more of things like "Giving people what they want makes it easier".
And then you got to squeeze it all inbetween the fighting and bloodshed. It aren't easy.
I have a good number of such talks with people daily. Get passed closed minds. People changing minds. etc. I could rake my brain and see if I could come up with anything to add. There's "patterns". But I'd also have to tailor to each character while doing that. It's a mtter of adaptability. Adaptation factors in a lot actually. Think of it this way. Remain sheltered only in what you know and you limit yourself. Branch out and explore in areas you're not yet comfortable with and you'll find there's nothing to fear/worry about. Provided the right context is established in those situations. Regardless of what dynamic you're going with, the same logic of "If you assume and didn't actually find out" can be used. What we really need is challenging people. with logic like that. This way you'd give the companions a reason to explore more with the player.
The "If you don't know then how can you know what you like or not or what you're interested in or not" can be very effective. Combined with other elements. Which could be all the more efficient on someone like Shadowheart. Due to her memory loss. Things will pick up once at Baldur's gate itself, so it will be interesting to see how far they push such things. For all characters involved.