As I said, I personally don't have issues with how the romances turned out in DAI. However I really don't see how the romance option in ME or BG or whatever effect the decision to limit male option so much in the first place. An eye for an eye is not a healthy point of view, just because female gamers had limited options in the past guess what, male gamers should get the same treatment.
I'm not saying that's what should happen. I'm just saying that straight male gamers complaining the one time they aren't pandered to is rather stupid.
Dragon age in general kept things quite equal until DAI. In origins you had 4 options 1 straight female, 1 straight male and 1 of each bisexual companions. In DA2 you could romance whoever you wanted since everyone was bisexual (not a good design if you ask me which is why I suppose it was changed). Then we get to DAI where straight males are limited to 2 options (1 of which female characters can experience in the same manner) while straight females get 3 unique romances (cullen, solas, blackwall) and 1 that is available to gay male characters as well.
Sebastian was added as a LI for f!Hawke only via his DLC, so even then, female gamers technically had more options (I say 'technically' since many players were disappointed with his romance).
As for Cullen and Solas, they have restrictions too. Cullen is only available to human and elven f!Inquisitors while Solas only available to elven f!Inquisitors. You can't romance either of them if you want to play f!Cadash or f!Adaar. Granted, it's not exactly something that would stop a lot of people since most people go with human Inquisitors, but still.
If you look at it from the unique romance side, straight females get 3 times what males get, which wouldn't be such an issue if the number of options straight males have wasn't limited to 1. Even Mass Effect 2, which was arguably the most imbalanced in that matter (from what I personally have played) had 2 very unique option for straight females.
tbf, both Cullen and Solas were added on as 'extra' LIs because BW had extra time on their hands. Since the amount of female characters was exhausted in terms of romances by that point, it's not surprising that the added LIs ended up being male (especially not in Cullen's case). Yes, Harding could've been made into a full LI, but 1) she wasn't an adviser or a companion, and 2) she didn't really have much content in vanilla DA:I when compared to everyone else.
I think it's more that BW was working with what they had at the point they realized they had extra time to work on 2 additional romances. Sera was already available to f!Inquisitors, Josephine was already openly available, Cassandra was already available to m!Inquisitors, and Vivienne was already non-romanceable, as was Leliana. Meanwhile, there was Dorian, Iron Bull, Blackwall, Varric, Cole, Solas, and Cullen for the male characters, 1 of which had been non-romanceable since DA2, and another of which wouldn't have made much (if any) sense as a LI. So BW likely decided to go with Solas and Cullen due to them being the easiest to form into LIs.
At least, that's how I see it. There were more male characters to choose from for additional LIs than there were female characters. It might just be that simple rather than it being BW pandering to straight women.