I think overall the change is supposed to be a buff in terms of the damage mitigated by shielding; in total. You do have to actively manage it, to leverage the benefits, as opposed to before. It does require a shift in gameplay and tactics. I like the change because it seems more powerful overall; provided you min-max.
I agree with the other comment that the gladiator may be able to better exploit the change through Lethal Defense.
One thing I found interesting is the shielding doesn't degrade over time as long as an enemy is in view. This can be useful if you're farming/levelling and there's a room with a piranha pool in the middle; giving you a bit of control if you disposed of a mob and took minimal damage.
Certain trinkets are more useful now, if say you got them through the random selection. I'm thinking of the vial of blood in particular. At +3, 10 dew gives pretty much a full heal. I imagine 5 would be enough to help hover around 50% health. I haven't gotten the vial on a recent warrior yet so I can't confirm. But 5 is quite easy to obtain.
Personally, I don't see it as clashing. The gladiator is the more active sub-class and currently, in the situation where you're about to kill an enemy but your shield is up, strategically, you should not end the combo and be in search for your next fight. Your shield will be in cooldown but you have combo built up ready for a finish and reset. The gladiator should be played differently than the berserker.
But the change you proposed shouldn't be game-breaking and it'll make some players happy so I'm not opposed to it or anything. It's probably a good change.