In my opinion, 1.9+ combat has a few good features, such as the shield, the ability to dual wield (unless you have battlegear installed), and the sweeping effect(good for survival). But I honestly think that in servers, 1.9+ combat for duels is pretty stupid. Here's why: Shield would be too op in servers, as you take no damage. Also, the idea of hitting and pausing before you hit limits your combo's, thus giving an opening for your opponent to attack. If you think about it, in the entirety of pvp, combo-ing is a key to winning. In 1.9+, you have to wait one second before hitting each time to actually deal damage. What are you gonna do? You're gonna have 3 not so good options. You're gonna either have to combo repeatedly doing 1/2 heart per strike, hit your enemy then run away until your attack recharges and face them again, or you're gonna hit them, take a break which allows them to hit you, and repeat the cycle. So in my opinion, 1.8 pvp is better.
I personally prefer 1.9 combat as it gives a different system opposed to just spamming the left click (the attack button). I do hope that they change some of the combat though because you only really have the option of a sword or an axe when you start.