I personally think all the versions have pros and cons, For instance, 1.6/1.7/1.12 are IMO the best modding versions, 1.8 is the best version for PvP, 1.16 is best for vanilla singleplayer/small SMP, and has the best block palette, the issue is it's not very optimized and is really rough on massive servers (Hypixel, 2b2t etc.), 1.13 is really bad IMO because it basically killed all previous mods and redid the world format and quite literally broke all previous map editors, while drastically hurting the game's performance, but 1.14 fixed a lot of the issues created by 1.13, and I loved the villager changes in that version.
Makaneek makes a good point down below with the concept of really large updates, and I agree with that, so 1.13 can be merited as a trend setter, but otherwise it's pretty bad. If 1.17 were to fix the issue of minecraft being single threaded (each server world basically only uses a fraction of your cpu) (biggest reason why it's considered unoptimized), and update the pvp to have higher skill requirements (basically all professional pvp players still use minecraft 1.8.9), and maybe some official mojang mod support ;), it would be the best version by far, otherwise, stick to the version that is best for your usage of minecraft.
