So what's the level cap now, or is it still 30?
Level cap is @ 20
After 20, you have to put on gear with Light stat that pushes you upwards to the max possible
@ Launch it was level cap @ 20, Light 30 (need +120 Light on gear (total), +30 on each of the 4 armor pieces to get there)
The Dark Below, cap is still @20, Light is now 32 (need +144 light on gear (total), +36 on each of the 4 armor pieces to get there)
House of Wolves (guesstimating) cap will be @20, Light most likely will be 35 (need +180 on gear (total), + 45 on each of the armor pieces to get there)
Guessing "Comet" Plague of Darkness will move soft cap from 20 to 30, so leveling up to 30 will be the new soft cap
Then new gear/light + stat will get introduced which will push us to 40
So that my theory
Then expansion III will be cap @30, with light 42
Then expansion IV will be cap @30, with light pushing us to 45
Then Destiny 2 rolls around and most likely 50+ level come sin and wouldn't be surprised if they go the WoW way of boosting people at least to 40 quickly