With the current system they have in place, i do not see them raising the cap. if they add a new tier of gear aka higher than exotic, or by allowing us to equip more than 1 exotic thats how we can get to levels higher than 30.
by making a legendary set better than another legendary set thats also better than exotics would break the game. there is new gear coming yes, but stat wise "light" wont be any better than current exotics. this game is not like other games where anyone can get to the level cap just by getting xp. lvl 30 in this game is achieved solely by completing specific activities and getting specific gear, with the new raid they are allowing another avenue to achieve level 30. Could the next hard mode raid be a level 32 activity, yes, if you could only get to level 30, wouldnt that certainly make it hard to do?
I just don't see a logical solution to being able to get to above level 30 especially if it's only 2 levels.