Tried to look at a SL2 in person ...

but could not find one.  I went to the one Best Buy in my areas that has  a good selection of camera gear.  No SL2 or 6DII either.  They did have the SL1, T71, 77D, 80D, 6D and 5D MKIV though as well as the M5/6.  Even though I couldn't hold a SL2 in my hands, i got some good feedback.

The viewfinder of the SL1/2 is bigger than the T7i/77D.  I was surprised that this was really a noticeable difference.  I have a SL1 and would describe its viewfinder as 'workable'.  I wouldn't use that word for the T71 or 77D.  With my glasses on their viewfinders were not usable and even with no glasses they were noticeably smaller than the SL1.  I really wasn't expecting this much difference.  Next up for comparison was the 80D.  Much bigger VF.  Very usable.  However the body is the same size/weight as my 6D.  Don't see any purpose of an APSC camera that big.  I did compare the VF of the M5 and it is much bigger and easier to see than T71/7D or even the SL1.

The body size of the T7i/77D seemed like a good compromise.  Bigger than SL1, but much smaller and lighter than 80D.

So having gotten an idea of the camera size/weight and VF experience of the various Canon APSC cameras i think the SL2 will probably be my next purchase.  The 6DII doesn't seem like enough of an improvement to change out my 6D right now.  I do think the SL2 will be  a significant upgrade over the SL1 (except for the removal of the eye sensor) and it is affordable.

If I could put the best of all together i would probably make a 77D with SL1/2 viewfinder.  The 80 VF is even better, but I know it adds a lot of weight due to being a pentaprism vs pentamirror.

Or maybe take the SL2 and add AF from T7i/77D and put back the eye sensor.

Oh well I can only dream.