they usually uncapped tomes, and remove lockout from coil, when a new coil was released (every 6month)
so im pretty sure the poetics cap will remain until expansion, as well as final coil.
then when expansion comes, they will make it unrestricted, so you can gear up alts. doubt they'll do that before expansion.
WoD will probably be ilv 110, so they wont uncap 120+ until you can get higher lv gear, from other raids, which is in expansion.
new dungeons in 2.5, will probably be ilv 100.