I honestly don't understand why anyone would want to go back to 1.8 combat. Back then, saying you were bad at PVP just meant you couldn't spam left click as fast as other people. The only "strategy" was having the best sword, the best potions, and the best armor, and running and jumping if you're low on health. 1.9 added strategy to weapon choice (should I pull out an axe or a sword for this situation?) and a WAY better shielding mechanic. I'm sorry if people who liked 1.8 combat find this new system challenging, but it is going to be challenging if you're used to a system that can barely be called a combat system.
ANYWAYS, if servers really want 1.8 combat, there's a very simple fix. Items now have an attribute that determines how long it takes to recharge, which can be set to immediately if the server host wants it. Or, you could give everyone max haste. There are pretty easy ways to simulate 1.8 combat in later versions, so I don't see why we would need this.