The only thing I can think of that we miss at DVC resorts over the moderates is the food court area.
For us, this is a big thing that we still miss. We love the mods - main three reasons were whimsical and elaborately themed "fun" pools (Aztec temple at CSR, pirate ship pool at CBR, Mardi Gras at POR) - I think most of the deluxe pools just don't have the whimsy of the moderates. We also liked not sharing busses and having multiple stops so that there was always a stop near the room. And the food court style/CS dining options at mods can't be beat.
Overall resort ameneties are better at deluxes - rooms are nicer, TS tends to be better, resort themeing and service is better.
That said - here's how the DVCs stack up in terms of what the moderates do best:
OKW - Bus service? not shared, multiple stops Whimsical pool area? there's a sandcastle slide
CS dining? AWFUL - a to-go window with no indoor seating.
SSR - Bus service? not shared, multiple stops Whimsical pool area? there is a water play area, but it's small. CS dining - Yes, with a limited menu. Plenty of indoor seating.
VWL - Bus service? not shared, single stop Whimsical pool area? Nice, but not whimsical (themed like a state park). CS dining - Yes, with a limited menu. Plenty of indoor seating.
BWV - Bus service? Shared with Swan/Dolphin and sometimes Yacht/Beach (but to AK) Whimsical pool area? Yes - circus/carnival theme CS dining - AWFUL - to go-style, no indoor seating, very limited menu
BCV - Bus Service? Often shared, depending on destination. Whimiscal pool area? THE MOST WHIMSICAL POOL IN DISNEY!
Sand bottom, Shipwreck water slide, multiple water features. CS dining - to-go windows only, limited indoor seating, limited menu
AKV - Bus Service - Jambo/Kidani share a bus Whimsical pool area? Not at Jambo, Kidani has a whimsical pool with an interactive water area themed like an African camp CS dining - good variety and plenty of indoor searing at Jambo - NONE at Kidani.