The only potential problem I can see in the future is new vs existing players. And it may not even be a problem depending on how they itemize it.

Say the level cap is 70 at some future point, and the ilvl cap is like 150. If a fresh 70 comes in with ilvl 70 gear, they are up to 80 ilvls behind the existing playerbase. Currently, a new 50 is at most 40 ilvls behind the top players. When the ilvl outpaces the real level significantly, it increases the gap between new and old players, possibly intimidating people from trying to get into endgame.

Now, this isn't a problem at all if a fresh 70 were given, say, ilvl 100 items when they capped. So like I said, it's just a case of how they itemize things.