There are a few patterns we can see when looking at the epic pools available to sentinels. Namely the elemental-themed ones, Ice, Fire, and Electricity, share some similarities in terms of function, but their AoE immobilizes are not aligned with the original versions of those powers.
Frostbite from Ice Mastery, and Fire Cages from Fire Mastery, have a property that says "100.00 knock protection for 10.00s on target" which prevents targets affected by the immobilize to be knocked down. The original versions of these powers from Ice and Fire Control don't have those properties (anymore), but the Sentinels' versions do. This proves problematic for a whole bunch of reasons, which means Sentinels are potentially sabotaging their team by using these powers.
They should all be standardized, so that they behave similarly to the powers they were based on.