We can't use Stormalong Bay if staying at Boardwalk. Which to me, I really could care less. Stormalong Bay did nothing for me when we stayed there a few years back.
To me, it's all about overall theme of the resort. That's where Boardwalk wins for me. My wife is all about staying some place different. Guess who will win?
I always have to vote with the wife, lol.
The pool at BC does nothing for me, either. I actually prefer the BWI pool, but am not coulrophobic. But if I were picking, for pool alone, I'd go with the Dolphin. It's good for laps early in the morning.
Before I stayed at either, I thought I'd prefer BWI. But BWI was booked and BC had rooms, so I went there first. Having done both several times, I prefer BC. It's just brighter and cheerier. Cuter. But BWI is fine. The rooms aren't as cute as BC, but they're cute enough. And if you stay club level (which I honestly can't advise, really not worth it, IMO) they leave taffy on your pillow. BC leaves those crappy Andes chocolate mint things in the green wrappers. At least they used to. I quit club level years back.
I don't like BC if I don't have a full balcony. The time on the patio/balcony is "up there" on my list of Vacation Stuff I Like. Those itty bitty balconies serve almost no purpose.
Plus, I'd rather stay at the BC with a view of BWI than the other way around.
BC, contrary to what you often hear, can shave ten minutes off your walk to Epcot. The walk to Epcot from BWI is quite short in the morning, but the walk back is very long on the way back at night.
Good luck on your choice!