if the eye relief is too long, you'll have a harder time finding a spot to mount it in order to get a proper cheekweld, you'll also need to be careful when choosing rings for it, you may have to go with cantilever rings set like LaRue's SPR/EER, if you can't move the scope forward enough on the upper receiver.
Now if you have a URX or MRP rail handguards that have continuous rails and are stable enough to mount optics on, that would alleviate some of the concerns, as you can move the scope back and forth as you wish. Or yo have to get a riser that extends beyond the upper receiver, like ARMS #36 or #38 extended.
But still that's a lot of scope for the AR, I'd go with NAG's advice and get a 3-9x.
See what I had to do to get this long eye relief USO SN3 to work on an AR?
This scope is now where it belongs, on a Remy 700