I re-watch the original movies quite often. As for the series... TOS and Next Gen are extremely re-watchable to me. The rest, not so much. I do love me some Janeway, but I just never really got into Voyager as much as I thought I would.
I've almost completed my re-watch. Took me two years to watch VOY, DS9, ENT, TOS and TNG (finished that one last week). Only TAS and the movies left now. I forced myself to really watch the episodes I thought were bad. Turns out many of those weren't as horrible as I remembered, and some of the supposedly good ones almost made me fall asleep... Some surprises: I actually like Enterprise Season 1/2 more than S3/4 now. Weird. And TNG was not as good as I remembered, especially season 6/7. VOY has aged a lot better. DS9 is mostly the way I remembered it, but unlike back then, I can now admit that I just don't like the Dominion War. At all.
Why don't you like the Dominion War? I liked the war bit, but not all the sub-par filler episodes in between the war episodes.
I am right now 190 episodes and movies 'into' re-watching every live action Trek. I began 191 days ago. You see, July 22, 2014 I began a two year StarTrek Mission. "StarTrek's 50th anniversary, 2016: The only one that will ever happen in history. This is the journey of the space shuttle TYGR. Its two year mission: to explore everything I can about StarTrek, to seek out new Trek information and new Trek experiences, to boldly cram as much StarTrek as I can, including the 50th celebration in LV, by the actual anniversary September 8, 2016." Which includes a complete re-watch of live action Trek. Star Trek The Next Generation Deep Space Nine Voyager Enterprise the 12 current Trek movies the 13th movie in 2016 (it WILL happen on time!) and Galaxy Quest (which to me 'has been and always shall be' a Trek movie) I've re-watched all of Star Trek (+ The Cage), all the movies to date (+ Galaxy Quest), and three seasons and 23 episodes of the fourth season of NextGen as of today.
I am doing similar. Actually 'focusing' on each thing I watch, thinking about each one, and writing down my 'experience' of each one. I'm definitely experiencing some surprises too. Not necessarily yours of course, but some big AND REALLY SURPRISING surprises of my own.
First I will tell you that Star Trek is on free TV in Germany for years. If you want it and if you have the time, you can rewatch the whole series`.There`s TOS, TNG and Voyager nearly every day. Some times they try to show DS9, but after a few weeks they always skip it. I never tried to rewatch a whole series , because I don`t have the time to watch episodes I don`t like. And there are some. Regulary rewatchs I only do with Voyager (my fav) and TNG. TOS I only like for some movies (II, IV and VI). It`s too old to watch and every time I try to watch DS9 I give up. I don`t like it. Don`t know why.