A very detailed and useful review, sithstar. Always good to read

On the placement of the covertec, I think it's one of those things that differs for everyone. I like mine exactly where it is on the Shock because it's out of the way of my dominant right hand for single hand use. For two-handed wielding I adjust my grip slightly so my right thumb sits on/near the activation switch, which puts the covertec wheel right up against my left fingertips - for me, a really comfortable arrangement. For a left-hander (like my wife and daughter) the opposite arrangement probably would work better - although they both have small hands, so it may not even be something they'd notice.
However, I recognise that for those who carry a 'sabre around on their belt a lot, a different setup may suit better. I have the wheel at 6 o'clock from the button on a couple of my hilts (it's the standard placing on the Consular, for example) and it's nice and symmetrical there, but I do find it gets in the way of my left hand when duelling.
I'm not sure there's necessarily a single right place that's suit everyone. I've seen a few with the wheel on the emitter, but that really only works with the simpler hilts like the Aeons. Even then, you have to work around the retention screw(s) so you can take the blade out.
As has been noted, it's easy enough to pop the wheel off if you're going to be duelling/spinning for an extended period - but not something that's entirely practical at a con or whatever.
Glad you liked your Shock in the main, though. As for the thickness issue, I recommend that you avoid the Guardian and Mantis in future - both are even chunkier than the Shock. The Manticore is comparable. For slimmer hilts, the v2 Aeon/Dominix, the Catalysts, the Sentinels and the Prophecies are all favourites because they have noticeable choke points and/or are more slender hilts.