Or, they can do exactly as they've announced, and leave the gear alone and just give 50s their own bracket. Seriously, expertise exists to differentiate pvp and pve gear, and it succeeds in doing that. The exact maths with expertise and the warzone lvl buffing may need adjusting at some point in the future, but that is entirely besides the point. Once we have enough 50s, they will be bracketed off on their own.
The results will give pve'ers the best pve gear, pvp'ers the best pvp gear, and allow those leveling to pvp as much as they want. I don't see a problem? Maybe the level buffing in warzones could be tweaked so the low lowbies aren't a joke, but that's about it.