The sword isn't overpowered. It works the way it's supposed to. That's like saying that the Rocket Launcher is over powered because it's not as easy to dodge it anymore. Or like saying the plasma grenade is overpowered because it sticks to you instead of bouncing off like a frag. Or like saying the grav hammer is over powered because it has an area of effect. The sword is a power weapon, and there is only one on most maps. And where there is a sword, there is a shotgun, so it's not like the sword is unstoppable. You can five shot a swordsprinter with a DMR pretty easily if you are any good. The sword is supposed to be a weapon that kills it's target. It's been like that in every other halo game it's been in, and it hasn't changed that much. The only addition that might be problematic is evade and sprint, but guess what? People can only evade twice, and sprint only lasts ten seconds. It's not hard to run away from the guy with the sword. Especially since most people use Jet-pack these days.
When I grab a sword, I want to be able to kill people with it. It's like with Halo 3, when everyone had a sword at the same time, except you don't need to have one to block it. It's annoying and makes the sword almost useless, making the shotgun a whole lot more powerful than the sword instead of maintaining a balance between the two CQC weapons.