This is a promising start, but just two buttons and no wheel means offloading too many commands to the left hand in games, and having to switch to another mouse for non-gaming tasks.
Wheels are heavy, so the best path might be to add more buttons. Subdividing the top shell into 4 buttons would allow you to have both a dedicated MMB and, for those cases where MMB is bound to something, a scroll-mode button that sends wheel-up and wheel-down messages based on mouse movement (you see this on laptops sometimes, though it usually replaces MMB, which is non-ideal). Another possibility for adding buttons would be to put a thin squishy layer over the carbon sides with a set of membranes in between; this *would* add a bit of weight, but would also make the mouse more comfortable to use, and address concerns about potentially having to hold the mouse too tightly to deal with the smooth carbon surface. I used to own an R2 Omnimouse, with no wheel but four top buttons and three side membrane hotspots (on the right side, which makes sense: for fingertip grip, the mechanical grip you get from your thumb is too important to move it to press a button, so any buttons on that side would only be suitable for very low frequency commands), and, once I'd programmed it with a decent set of gestures, never found myself wishing it had a wheel.
Also: +1 for "holes are stupid". There's no way having the PCB be that exposed can be good for longevity!