would start with the parks.
which one are you spending more time at on this trip>?
MK and Epcot - BLT or VWL
Epcot and Studios - BCV or BWV
then you say you liked slides
BCV does not have one - but it shares with BC/YC - SALB - and this is probably the best pool on WDW resort property.
for MK area - would go with BLT (now also love VWL) - but the views from some of the rooms at BLT are special. the slide at BLT is small and fast.
to me it is not fun to be at an Epcot or AK and want to spend alot of time at MK - better to be at a MK resort.
same for Studios - if you are spending alot of time at Studios - then definitely go with a Epcot resort.
BLT because you can access the monrail is almost as good as walking back to BWV or BCV - but not quite.