My rig, is configured specifically for boat. I use ring bungees on the top mount which reduces faff
I can (and do) either giant stride, or back roll, often with a dpv as well for good measure. So far zero set up and water entry issues, and I'm more often than not, faster in my gear than normal BM rec divers
For exit - I tidy up the rig on my SS, then depending on the boat, ladder, sea state, I can either hand up my cylinders, or ascend the ladder with both (al 80) attached. At the surface, I generally un clip both rear attachments even if I'm climbing aboard with my cylinders to make it easier to fully release once onboard
I always have fresh cylinders for a dive, so I have cambelts on the tanks for fast changing, again I can switch both my tanks in the same time it takes for most people to swap their BCD over
Some of the resistance to SM has been caused by SM divers being ill prepared and faffing about causing delays to others.
I spent a lot of time tuning my gear, for instance the slings are customised to ensure they not only slip onto tanks quickly but that they repeatably sit in the correct position each time. Similarly all my releases are setup to ensure that I can easily self fix the cylinders either seated or standing with zero need for assistance (although I'll never refuse help), while ensuring they are properly in trim underwater.
If the majority on my SM diving was say, at an inland site, with steps in and out and easily ability to kit up in shallow water, then I might reconfigure my kit accordingly if there was some benefit
Sometimes people blame the system, when really it's the user not having not thought things through, nor perhaps tuned their gear to their way of diving and needs