Personally I think trans should be de-categorised yes. It's easy for me to say as a pansexual, but porn is already a minefield of weird shit I don't want to see and trans or intersex folk is not one of the things that puts me off. I wonder if it's really right that anyone should feel otherwise? Seems like a lot of that may stem from homophobia really... Like if you go to a porn site not expecting to see various naked strangers who may or may not fit your tastes... i um... i dunno what to tell you?
If it were up to me, porn would be set out like a dating site, where you use a tags-like system to "opt in" to categories you are interested in. And by default, all races and genders (and trans/cis status) would be included as "normal" and you then can opt out of certain genders or ethnicities and into like... foot stuff or people bathing in baked beans or whatever.
But even with porn sites set up as they are today, there's no excuse for using inaccurate, misgendering terms like "Shemale" or "Trap". I've asked some trans women friends and they tend to agree that "chicks with dicks" would still be less offensive, because at least that describes a certain identity for how it is. But the preferred goal is of course not to be treated as abnormal, nor misrepresented as a narrow stereotype when trans people can have quite a range of appearances and sexual characteristics.