Water would benefit immensely from some sort of PC.
Do you consider NT quanta denial?
It is, potentially, but it's extremely weak and very rarely usable as such. Similarly, Ice Bolt is weak weapon control, although it is actually usable - in a stall, where stopping something like Fahrenheit for a few turns is possible, it can actually be relevant. We also have Trident, which is stronger quanta denial, and in fact we have Tears on a stick in the form of Nymph Queen, so we technically have four PC cards! Amazing yes?
The issue is, while we have decent quanta control, and even a possible form of weapon control, we have no shield control...and that's what we really need. Ice Bolt does bypass shields, but it's often simply not enough
PC itself doesn't need to be the answer, to be fair - oETG, for example, has implemented Waterfall, which is Momentum on a stick. Not only does this help the shield problem, it also helps the weak duo Gravity synergy I've addressed, and would be a fantastic addition.