Thank you everyone for your useful advice and interesting discussion! I learn a lot through reading your replies.
Just to add a bit more.. today, the typical 8 inch F/5 rides on an EQ mount, most likely an AVX. As long as the mount is reasonably well aligned and tracks reasonably well, coma in planetary images should not be an issue.
My friend Jack has a Celestron 8 inch F/5 mounted on an AVX. It seems to work to the seeing limit.
To Richard's point, Tinker's versus Hands Off.
The first time Jack showed up at my place, the scope was quite difficult to use. The stock focuser is a rack and pinion and I gave it my normal rework and replaced the pads with Teflon. It was better but still not good. Rotating the tube for comfort was difficult and risked the tube slipping and/or the mount losing alignment. Viewing Jupiter with the eyepiece pointed straight at the ground is not optimal.
Jack is a tinkerer type, a hands on guy his entire life. Over the period of about a month, Jack had modified the scope with a hose clamp and part of 5 gallon paint bucket and a little grinding on the rings so now the scope rotated in the rings smoothly and without risking losing alignment. He also added a sealed back fan to cool the scope. The third thing was a better focuser which we installed together.
The difference those three modifications make is remarkable. The scope went from being.. "It's too awkward and clunky, I don't want to bother looking through it" to "Wow, this is really nice, comfortable and it provides some awesome views." It was a total transformation..
Jack has the GSO ComaCorrector. With my 35mm Panoptic, it provides a 2.0 degree TFoV and some beautiful wide field views of the Veil and many of the deep sky wonders of the summer skies. The North American Nebula is quite stunning, it's enough aperture to provide a very bright image for use with a UHC filter with enough magnification to see some real detail.
That won't be happening with an 8 inch SCT.