I concur with @nielsent, Mala Wharf is awesome for shore diving - as told by divers I met there (though I didn't dive it) coming back from diving with Extended Horizons.
I did Mike Severn's to Molokini and the 2nd dive was closer to shore. Excellent dives, excellent op.
Extended Horizons will take to to Lanai for Cathedrals (from Mala Wharf) - which Sylvie & I liked much better than Molokini, for the scenery, the lava tubes, etc. However current was awful back & forth, hard to stay still even at 50 feet.
Molokini and the second dive where a walk in the park.
To me, Molokini is visited too much, much like the "popular" dive sites in Grand Cayman close to shore / Seven Mile beach, the reefs are not as pristine as they could be.
You might see some big stuff, or just a reef wall with some activity and the usual pacific critters, fish too accostomed to visitors.
Instead of staying deep, the stay at the top, waiting for a snorkeler to feed them (when he/she vomits).
You might kick yourself if you don't do Molokini...it's the signature dive spot. If you like it a lot, and weather is good, you can do the outer wall.
We were supposed to do the outer wall, but the waves were too high. High winds that week when we were there.
If you're a good diver - good on air - the DM/guide will bring you deep to see endemics. We weren't that good, having to head back up after only 10 mins at 100 feet. I take awhile to equalize & such.
Mala Wharf - where Extended Horizons leaves - much closer to where you are staying than Mike Severn's, making it a little easier for the 6am departure.
IMHO - do a trip with Severn's, a trip with Extended Horizons, then just do a whole bunch of shore dives !!!
Get off the beaten path and dive where the reefs are rarely visited - thus the best fish behavior to watch.
Shore diving around the bend of Little Beach and Big Beach, also North of Little Beach. Or just snorkel / freedive it. Big beach was our all-time favorite beach in all of Maui.
BTW - lots of turtles !!! Saw some every day.