Unfortunately Disney only discounts room they need to fill, so that means no discounts for categories that are already sold out at rack rates.
In the past I’ve had great luck finding discounted garden views at BWI, and have seen standard rooms as well. The water views seem to be rarer and get snapped up more quickly, but I have seen them. This year and next all bets are off, though.
My advice is to always, ALWAYS initially book the first choice of room that you are willing to pay rack rate for. Then
when and
if discounts are announced, rebook to whatever looks best at that time. Sometimes you have to be flexible.
If you are OK with paying rack for water view and are simply hoping for a discount, by all means stick with it and budget other stuff accordingly. BW view is great! But if you are pretty certain you will switch without the discount, then book your first choice of room in your target price range
right now. Waiting runs the risk that you will have less to choose from in the future, and holding the room actually lessens the chance that it will be discounted.
FWIW, Disney does allow you to hold two reservations at the same time, provided you are willing to pay the two deposits. I try very hard not to do this, but a couple of times I have done so when the my party size, hence the room category needed, was uncertain. I cancel the spare room as soon as I know, to make it available to someone else.