Okay this is annoying for a start. There are many reasons, some major some minor, on why we should disable player pushing. Player Killing - If someone AFK's on their island you can happily walk up to them and push them off and then they die. :/ Drop Parties - 1.9 ruined drop parties, as we keep pushing each other and it's more unlikely to get drops. Parkour - This doesn't happen often, but some people race on the same parkour, they'd end up killing each other trying to win. :/ Farming - So you're at /warp animal or /warp mob and someone spawns a truckload of pigs or something, then you're stuck being pushed around in places you don't want to end up going and it's annoying. Post down other reasons why it should be removed, and feel free to support or not.
Technically, it's called the Collision Rule but never mind that on to the suggestion. :b In my opinion one of the easiest ways to solve the issue is to play Minecraft with one of the 1.8 versions. The server's version is 1.8-R0.1 which means that technically the Collision Rule doesn't exsist server-side quite just yet. However, if the server was running 1.9, there are a few plugins that disable the Collision Rule as well as that there are also scoreboard commands which can disabled the Collision Rule. For me, I don't really mind it that much but I see your point. So, I'm going to say Neutral on this.
I don't know if they would be able to get rid of it since it's apart of the game, but if they could support. Sometimes I do use 1.8 but I wuv my hats too much :3
