Well here's the deal,
Sentinel has this passive where if you and the support hit the same target within x seconds, the triggering attack deals a % of the targets max HP with an on target cooldown to follow. Since you've played her I assume you know that part already.
The damage is now 2% less at early levels(down to 10% from 12%){ now 10%, 12.5%, 15%, 17.5%, 20% instead of 12% 14%, 16%, 18%, 20%), so it drops her lane harass a bit, the on target cooldown is also 4 seconds longer (10 seconds from previously being 6 seconds.). This drops her lane harass a bit more.
Furthermore Her ultimate's cooldown is now 120/90/60, instead of previously being 90/75/60.
Overall her late game is identical aside from the on target cooldown of Sentinel, but her early game is a bit weaker. So if you did well with her previously, it shouldn't be much of a problem for you at all. People who were, just okay, with her will probably have some issues.