Is that disappointment for video or does it include text?
not the person you've quoted. i was disappointed no OLED too because that's what i'm used to now. got an oled phone/oled tv. honestly i think the iPad screen is
really good.
i've been comparing the screen on a 2019 iPad 10.2" to my 12 Pro Max. yeah the OLED is better but the LCD displays Apple use are arguably the best out there. I think the display on the iPad is just as good as or even better than my £500 LCD monitor that i calibrated for photo/video work.
I had my iPhone and iPad next to each other trying to tell the difference. OLED is slightly more vibrant but I'm impressed with the colours on the iPad. When comparing app icons with blacks/dark greys the OLED is only slightly darker. Remember I'm comparing them side to side which isn't what people are gonna do. I even checked the display using
http://www.lagom.nl/lcd-test/ and again i'm impressed with the contrast/gamma/black levels.
Where the LCD on the iPad falls short is at high brightness displaying blacks. At low levels the blacks are absolutely fine but if you're running an app in dark mode or watching a video (with black bars) then the LCD just can't compare to OLED. The entire screen will glow on the iPad but the oled the backgrounds/black bars are inky black. i cant get HDR on the iPad but i imagine if it did support HDR that it'd be about the same experience as HDR on my monitor. an LCD can only put out a single uniform brightness across the entire panel so when i watch HDR on my monitor it looks better but the blacks are glowing which is not good. the mini led iPad will be able to dim black areas so HDR on that will be much much much better.
now remember i was looking at a budget iPad from 2019. I haven't seen what the displays are like on the iPad Air or Pro. Maybe they are better but i'm not expecting miracles. The quality might be better on higher end models but it's still an LCD.
TL;DR: i think that the iPad has a fantastic display that comes quite close to OLED but where it falls short is when there are lots of dark backgrounds such as using dark mode or watching movies in particular HDR.
Super TL;DR: most people will be happy with LCD unless watching video outside and/or in HDR.