Fair enough, everyone is entitled to their opinion...
The vents do work...their purpose is to aid exchange of air between the inside and outside of the tube. If there is appreciable difference between the two temperatures equilibrium will take its course. I chose to add the fans to aid the process in when there are rapid temperature changes, like at a dark site up in the range. That was my choice to enhance a feature already provided. With the conventional SCTs the air is trapped and the air inside the tube only grudgingly gives up some of its heat. That is a much worse situation IMO. I'd actually like them to make the vents larger than they did, but horses for courses. Sounds like you've found the solution that works well for you.
You could argue that having a corrector plate out there at the end of the tube, exposed to the atmosphere and all its moisture is fundamentally flawed, and you'd probably be right...but that hasn't stopped you buying them repeatedly over the years
the requirement for dew heaters with an SCT is well documented in all but dry climates.
While your concern about the lens is real, it's only really justified if in practice they do indeed get dirty and require cleaning. I've had my scopes for over 5 years now and there's no visible signs of that being the case. Is it safe to assume you also don't own a refractor? That would no doubt throw up the same concern because unless you take the lens cell apart, most of the surfaces would be otherwise impossible to clean. I've also not experienced them dewing up, and I've lived in both the UK and Brisbane in the time I've owned them. They're just not exposed to the elements as they're in the baffle tube.
I'm not sure where your impression comes from regarding the focal plane...it's not critical for visual observing under normal scenarios. I use a variety of eyepieces with my scopes from short focal lengths for planetary observing all the way out to 40mm extra wide designs and have never seem any issues with what the scope/eyepiece is presenting that can't be corrected by my putting on my glasses
using barlows, flip mirrors, ADCs...none of it causes an issue when looking at the centre of the image.
For imaging, the focal plane is quite specific...the same is true for many imaging scopes, however, regardless of designs. The optics involved in the imaging train and the flat nature of the imaging sensor chip up the ante. Using a DSLR on the f/6.3 reducer is equally picky about the lens-to-sensor distance if you want anything like round stars across the field. The bonus with the Edge HD is that you actually DO get rounds stars across the field
Btw, I'm not trying to sound awkward/funny, it just sounds like you needed to get something off your chest and I'm trying to give you some perspective...