Just about any of the Kihei boats are smaller so less divers since most launch from the Kihei boat ramp. I often suggest Severns also - just beware that they like to leave at or b4 6am if possible to be at Molokini first.
Lahaina Divers has 2 big Newton dive boats. On their website they show a group of divers but they'll segregate by level and aasign a DM to every 8-10 or so. Cathedrals is the signature dive but I also like the sites around Sharfin and points west - for some they may look for Advanced or equivalent experience but there's ofen two dives you can do also at the same site.
The other Lahaina boat options are Extended Horizons or Hawaiian Rafting with their big RIB. It can be a little rougher at the Cathedrals at times so a bigger boat is better.
Maui Dive Shop also has a big boat moored in Ma'alea - a few minutes north of Kihei. They feed divers from all their shops there - I've been on it once but won't again - too crowded
Only Lahaina Divers goes to Molokai for the hammerheads. I believe some times of year are better than others but have not done it.
I agree the South Maui shore dives are good options - in fact they're better than anything offshore in West Maui IMO except maybe Mala Pier. You won't really get a lot of depth anywhere just off Maui though - maybe 60-70'. A site like Black Rock is closer to 40' - near the back it's shallow enough that a good snorkeler can swim down.