Just to carry over something from another thread. Maybe this is something we will see in a month or two. When moving tabs around, you must press and hold before dragging, which is different to the rest of the OS, and is a little bit cumbersome, so perhaps they have already reserved instant swiping for features they are not quite ready to let loose
I certainly don't believe that swiping back and forwards is a make or break requirement for a tablet browser though. Convenient, sure, but it's really not very much effort just to press the back button (one of which is located right where your left thumb would sit)
Don't think of it as features they have taken away (it's a brand new browser after all, so you can't take away what was never there), just think of it as something they have yet to implement. Anyone on the TP will know what kind of pressure MS have been under having set the launch date in stone. It was only the very last couple of builds that were anywhere close to being launch "ready". I'm pretty sure they had to push back some things (i.e add-ons for edge) so that the actually vital stuff was all up to scratch.