A lot changed in 1.8, I don't know the specifics but if you pvp on the 2 you'll notice a big difference in how you hit people, how you combo them etc. this is why HCTeams, Badlion, Kohi etc. stayed on 1.7.
One thing I really hate about the way Minecraft's gone is that all the big factions server have been killed off by shitty games server. There are no faction servers with a decent amount of players anymore.
