I don't like renewal because of the way they changed a lot of things people enjoyed. Instant cast, skill delays, cast times, aspd, defence, formula changes. And a lot of the things they added were brain-dead decisions, most of which didn't supplement what already existed - rather, eliminated its purpose.
A lot of us are still stuck in our ways. Renewal feels like the highly customised servers many loath. There are some ridiculously overpowered things which don't add to the experience.
So yeah. My overall feeling towards it is Renewal didn't supplement an already great game, rather, it changed the way it worked and removed a lot of elements people enjoyed.