Often said:
I'm amazed by how many people imperiously claiming that this can't be an x-wing because the wings aren't open seem to completely forget that the wings CLOSE even in the very first movie.
Plus it's 30 years later. Couldn't designs have... modified? Look at military jets 30 years ago compared to today.
The issue isn't that they have a new X-Wing design for the new movies, the issue is that after JJ took a massive shiny Apple-store dump all over Star Trek, and given his attitudes, a lot of folk don't trust him to actually have this be a "new" design at all. Ralph McQuarrie's conceptual work for Star Wars is stunning, but for 99.99% of Star Wars fans, it's something they experienced
after the movies(if at all), and if JJ ends up retconning this new design as being "the" X-Wing, the Incom T-65, yeaaaaah that's not going to go down well.
He may not, he may as theorised cast this as a new model, or a refit of the original with updated engine tech or something, but his recent track record robs him of any right to expect the benefit of the doubt.