It does appear on paper that some of the tsdz2 shortcomings have been addressed. Obviously will want to see that reflected in real world experiences.
As for the motor incorrectly mounted, I am aware that the tsdz2 case is prone to shearing if not mounted correctly.
I think there are some open questions on thermal conductivity / management. I think part of the tsdz2 issue is that there appears like there is little thermal protection. It would not be so bad if the motor reduced output or cutout if overheating. As an end user, how are you to know if the motor is working too hard for too long? I know you can add a sensor to the tsdz2 and use osf, but I'm talking out the box here. From what I understand, the aftermarket thermal mods to the tsdz2 are actually quite effective and simple. The 1.6mm aluminium bridge between the motor and housing looks good, wish I could find a source in the UK...
One of the other big reliability issues with the tsdz2 is water ingress. I know this is tough to solve, but it is important. Not heard anything about this on the ToSeven offerings yet.
I don't know how big an issue the blue gear really is. Cost wise, if it needs to be replaced every few thousand miles then not a big deal. It's not hard to replace but also not completely trivial. The main issue is the hassle factor I think. I suspect it becomes more of an issue the more power you try and put through the motor.
I would hope that my tsdz2 will be good for > 5000 miles with some blue gear / bearing replacements and good care, that's about 2 years of cycling for me. If it's service life is less than that it does not really stack up financially. If say I was going to pay double the price for a motor, I would expect the service life to double as well. I'm currently on 400 miles in 4 weeks.