Yes, obviously the expiry date of the contract will have some bearing also. To be perfectly honest, if those 4 are your choices, this would be my opinion:
OKW or SSR - perfectly good choice. Need to be careful with OKW that the contract you buy has been extended (as OKW was the first DVC resort built, owners were given option to extend the contract by 15 years - if the contract wasn't extended, it will expire in 2042). You should not have any problems getting either of those resorts at the 7-month point (except for very busy periods).
AKV - If the value or concierge rooms are important to you, buy here. Also, very pretty around Christmas time.
BLT - Not quite as high demand as it was when it first opened but still difficult to get standard or MK view here at the 7-month point. personally, unless you really want to stay at BLT (and stay in a standard or MK-view room) I wouldn't buy here.
Obviously, all of this is just my personal opinion so take it with a pinch of salt but I hope it helps.
FWIW, we own at SSR but have only stayed there once in 7 years of ownership (and more than 10 trips).