I have no problem with it, but also don’t think it matters whether he’s 6’4”, 6’5”, 6’6” or 6’8” honestly. It’s like Wolverine. As long as he’s drawn shorter than the folks he’s around (except for Puck), it matters not to me if he’s at the proper scale, meaning 5’3”, or he appears to be a little taller than that (say 5’6” or 5’7” even). I’m just not a stickler for exact heights.
Cable should be taller than Cyclops, but shorter than Colossus. About the same height as Bishop, give or take an inch or two, which really doesn’t matter much on the comic page. That’s my $.02 anyway.