Yours is an impressive article to review the Meade 18mm UWA that details reasons for and against it using a wide range of equipment, thanks for sharing.
Since we last spoke I've had opportunity testing the new, striking 18mm 5K UWAs paired straight-thru with a small binoviewer on my superb Skywatcher 102 f-5 achromat (see attached). The "lean mean no green 18"
is quite formidable and made a pair of otherwise wonderful Smart Astronomy 19mm EF (extra flat) wide angles redundant. Magnification at 28x for a 3.5mm exit pupil (aka general observation use). Was quite comfortable to look over the wall-to-wall stars!
Additionally, I like the fact that the 18mm won't kidney bean as the 14mm 5K UWA does on bright objects like the moon. That is why I got them. Both BTW are razor sharp on axis fine for planetary, lunar and star clusters. M-42 was also well represented last night in the 18mm with much nebular extension around and off the finely delineated trapezium stars
In another 5K arena, I also find I prefer the 24mm 5K UWA to the 28mm 5K SWA. The field in the 24mm is somewhat easier to utilize now after its weight loss program, and it is somewhat more comfortable to look over "optically" than the 28mm. The 28mm is definitely no slouch though, it is bright and sharp and the eyecup actually is one that functions PERFECTLY with the embedded optics so as to smoothly adjust upward for that "just right" viewing experience!