[Hydra Spectre]

IMAX Enhanced was basically Missed Opportunity: The Display Technology.
In my ideal mind, the IMAX Enhanced feature was actually made for HD-DVD and Blu-ray and would have 1280x960p (720p), 1920x1440p (2K 1080p), 3840x2880p (4K 2160p) and 7680x5760p (8K 4320p) resolutions in 4:3.
My ideal IMAX Enhanced Blu-rays would be in a 4:3 1440p or 2880p container while the Blu-ray player can present it uncropped in pillarboxed 4:3, fullscreen open matte 16:9, the theatrical aspect ratio or anything in between, with the default setting varying per film.

There would've also been IMAX Enhanced 4:3 TVs in CRT (for monitors) and OLED (for TVs), with the largest ones of each being 40" and 100" respectively, according to my dreams.
The CRTs would also have perfect analogue compatibility for DVDs, LaserDiscs, VHS tapes and retro games, complete with scanlines for 240p content like your childhood NES, Super NES, Sega Genesis and PS1, as well as being as cheap as a poverty-tier 720p LCD TV, giving them an edge over the larger and sleeker OLED TVs.
A 100" 4:3 OLED TV would still give about 92" of screen estate for 16:9 content, and a 40" CRT monitor would still have a 37" area for 16:9 content, bigger than even ROG's largest 16:9 monitors (except for the large format ones) which top out at 32".
A 70" 4:3 TV would still have more than 65" for 16:9 content.
If CRTs continued to be refined to this day rather than being abandoned for being too bulky and small at the same time, maybe CRTs could've been better than OLEDs today.

There would be 3D for all these TVs in either passive (OLED) and active shutter (CRT).

If IMAX Enhanced was basically a program to make 4:3 modern again with giant-ass screens that would still give proper justice to 16:9 and CinemaScope content, I would love IMAX Enhanced. Instead, we got a THX-tier certification with limitations compared to Dolby Vision and Dolby Atmos.
In my headcanon dreams, IMAX Enhanced started with the HD boom of HD-DVD, Blu-ray, and the Xbox 360 and IMAX was basically repurposing 4:3 as a premium enthusiast format rather than an outdated dinosaur format.
Other people thought making displays wider would be better while IMAX wanted them taller and back to good old 4:3. Filmmakers like Christopher Nolan and Zack Snyder would’ve supported IMAX Enhanced 4:3 content.
It would give us full uncropped IMAX scenes for Nolan films and Zack Snyder would get less backlash for making films in 4:3 as it will be seen as a premium format.

Even films shot flat or in Super 35 like the Burton/Schumacher Batman films, Top Gun (500) Days of Summer, and even the cutscenes for Sonic CD (which were animated in open matte 4:3 but cropped to 2.2:1 for Sega CD and 1.75:1 for PC and consoles, but the mobile releases are in 4:3) would’ve had IMAX Enhanced home video releases that displayed them in their full 4:3 glory.
Video games would’ve also had IMAX Enhanced features with Vert+ expanded 4:3 FOVs for IMAX Enhanced TVs.

And IMAX Digital (aka. LieMAX) was another missed opportunity since it could've displayed 4:3 2K and 4K digital projections with huge screens like IMAX 70mm but they went for a 1.9:1 aspect ratio instead until the laser projectors came along.