I wouldn't be surprised if they wanted to do semi-holographic interfaces like we eventually see in most sci-fi from the 2000s and on. Those tricorders make a lot more sense if you pretend there's a holographic readout hovering above it.

TOS era tricorders had a small TV in them and big chunky buttons you could see poor Ensign Ricky fiddling with before falling into the lava pit. LCARS just didn't work well with the tiny little displays of TNG tricorders.