It always bugged me that they never took any Star Trek: TNG technologies to their logical conclusion. For example, if you can make "fake" matter in a holodeck, why not build the whole ship out of holodeck? Maybe a warp-core and computer in the middle, but the entire rest of the thing could re-configure or repair itself as needed. Made even dumber in Insurrection, where they did have a holoship but it was just a giant empty holodeck with engines.
And don't even get me started on the episode where the transporter made people younger, *and they treated it as a bad thing!*