Call it sentimentality, but I don't feel like watching TNG is
that difficult nowadays. It's old and missing some of the tech we have today, but if you can suspend your disbelief on that, it stands pretty well.
(To those who haven't watched TNG, the whole series is on Netflix, mostly (entirely?) in the remastered edition, so no TV-like quality. A piece of caution: this is not your typical sci-fi; it's much more positive about the future, science and technology than what we get served on TV these days.)
RE the yardstick thing - there's still lots of things that in Star Trek are shown as easy, and that they feel like they should be easy with sufficiently advanced tech, and that are still hard for us today. So it's maybe less of an yardstick and more of a goal / reminder that there's lots to be done yet.