Having rules text that lets you avoid arguments with players about weapons and whatnot is indeed a Good Thing. It's very easy for players to get excited about 4d6 greatswords or whatnot, and get quite annoyed and aggrieved when they are forbidden it; just like it is very easy for a DM to be worried about balance and the daft mental image of carrying around 10ft long greatswords, and get annoyed at being made out as the bad guy when (s)he forbids it. Regardless of who is right, both sides are likely to be annoyed at the outcome. So the way that Enlarge sidesteps the issue by saying up front 'here is how your weapon damage increases' is really good, and I think something that should definitely be incorporated into any new feature that has a similar effect.