Every time I watch a TNG episode I come to think about the gadgets they use on the Enterprise. Tricoders,communicators and other gadgets presented on the show look rather bulky for the 23th century. I know TNG was filmed until 1994 and when you look at it now, it's a classic. It was not hard to predict back then as It's not now that all hardware should be as thin as possible with nicely done edges etc. I don't think they were paying attention on how gadgets on the show will look like.