Yeah, it's somewhat of a catch 22 (or game of chicken).
If you have your heart set on a specific resort (or, in our case, a specific combination of resorts for a split stay), it's tempting to book at rack rate (and hope for a discount later) because getting the reservation at rack rate is better than not getting one at all (especially since you can always cancel). In addition, you want to get 180+10 for ADRs (sometimes discounts aren't available until after the 180 day mark).
But, as you note, if you do this, you lower your chance of getting a discount.
In years past, I haven't worried as much about lowering my chance of getting a discount by booking earlier at rack rate because it seemed that the resorts, particularly at the deluxe level, just weren't booking up that much prior to discounts coming out. But now, were seeing some resorts (or at least some room categories in some resorts) book up entirely before any discounts are announced.
So the game of chicken has become much more difficult, especially since Disney keeps resort occupancy levels confidential (unlike airlines, where you can see how many empty seats there are on a given flight).