Well, no, I wouldn't date someone. I'm happily married.

But before I met my wife, I probably wouldn't have dated someone who transitioned period, nor would I have considered dating a man. That said, I knew my wife transitioned when I met her (it was literally the first thing she told me), and immediately had my world view challenged. Here was this incredibly interesting and great person - should I run? Or should I make sure my prejudices are justified first - and be willing to change if appropriate?
Having seen that I had a warped view of gender, sex, and the "expectations" of society, along with a fundamentalist point of view, I think I would be open to many possibilities *now*. If I was no longer in relationship with my wife, I would seek out someone who has courage, strength, love, compassion, caring, confidence, and attraction to me. I'd want them to be interesting and funny. I'd want them to be attracted to me. I'd want them to have support - if they need a therapist, for instance, I don't want to be the therapist, nor do I want to be a parent, a teacher, or a nurse. I'd want them to be someone I'd have fun being with. And, yes, I'd want them to be someone who has a sense of joy in bed. All of this seems rare enough to find together that I don't think I should add a bunch of other things on top of it, like sex or gender.
So I'll side with people who have said sex and gender don't matter. But I'd add one caveat: I wouldn't want to date anyone who wasn't living the gender that they are. I couldn't be happy in a relationship where my partner was miserable. So if my partner was living honestly, and was f2ftm2mtf or m2mtf2ftm, I'd be fine.