I don't really see a benefit to Lamar's approach. The majority of new sidemount divers currently are cross-overs from BM at tech levels. Those people have ingrained skills routing the long-hose from the right hip area and around, with a short hose from the left on bungee. i.e. A typical hogarthian reg set-up. It makes sense to preserve that capability - and there is vast support for it's use, based on pros and cons. I'm not sure why sidemount would change that formula...
Where did you get this from?? Less than half of my sidemount students are crossovers from backmount tech levels. Actually most of them are just getting into tech and prefer to go straight into sidemount rather than doing backmount first.
I think you're making a big deal out of something that isn't a big deal. I don't see a problem with top mounted LPIs. I've had cave students that preferred to keep the LPI in the top mounted position. I personally don't care how my students rig their sidemount systems as long as it's not dangerous and they can trim out. And I don't see any danger in having an LPI route off the top. As I stated before, when I make an ascent in OW I do so in a vertical position so I can see where I'm going and make sure I'm not ascending into anything. With the cave model LT and sms50, this isn't possible. There is no dump near the top. Putting an LPI at the top solves this issue for anyone who isn't interested in diving in overheads. Could they have just put a dump valve on top and kept the LPI on the bottom? Sure. But you can switch the LPI and dump valve on the OW models.
Sidemount is still evolving. We need to keep our minds open to the different ideas that are out there. Stifling these ideas does nothing for the sport. I really don't think these new rigs have anything to do with bad instructors. They are simply a different approach to sidemount diving.