I imagine the going Xbox 360 -> Xbox 720 would just have been asking to people to joke about it being 720p (even if not actually, the picture quality joke basically writes itself).
The solution though was obviously not the brainworm reasoning that got us the Xbox One (nobody was going to call their console 'The One', cf. 'X-bone'). Your alternative of going straight to the Xbox 4 would probably have been considered a loss by the executives, but I imagine it at least wouldn't have been made fun of beyond the release period, since it would have been clear why they did the change.
The solution though was obviously not the brainworm reasoning that got us the Xbox One (nobody was going to call their console 'The One', cf. 'X-bone'). Your alternative of going straight to the Xbox 4 would probably have been considered a loss by the executives, but I imagine it at least wouldn't have been made fun of beyond the release period, since it would have been clear why they did the change.