I have played minecraft since beta 1.7.2 and most updates have improved the game. Some were rubbish but I feel the main updates that have really improved things are : -proper creative mode -command blocks -resource packs -data packs
They all helped to improve adventure maps. Older adventure maps are so lifeless.
Then again, I prefer minecraft for building rather than surviving which is why I like to keep up to date.
MC 1.7 was my goto for a very long time, especially for modded. 1.12 took its place once the mods were stable and there was enough content. Anything past 1.8 though really doesn't feel like oldschool mc anymore though.
i like 1.8 a lot since everything is so simplistic on it, even the servers which are 1.8 based are not laggy at all. handling 1.8 servers is REALLY really easy