Well there was a great deal of backlash over the impression that the companions in DA2 were a bonk buffet for Hawke, so perhaps they have decided to go for greater quantity of potential romances with a variety of different restrictions on them.
You could have -
Varric - gender inclusive but dwarf only.
Sera - gender exclusive but race inclusive.
Cullen - gender inclusive but class restricted to non-mage. (put down the torches, these are just random examples.!)
etc, etc, etc.
If you added enough gateways to the romances you could probably cut down the content to something consistent with the past games without too many problems because (as someone already mentioned) there are quite a lot of scenarios they're no longer accounting for. I'd probably personally enjoy this approach but I'm also fairly certain that I'm getting my Cullen romance for my preferred Inquisitor, so I probably don't have very much to lose by the implementation of such a mechanism.
I don't really think they're going to do it though, my guess is they will go with a 2-2-2 split to provide equal numbers of LI for different sexualities and that gender will be the gateway to the content.