if anything, you need to make new, interesting mobs with different characteristics. as in completely forget about archetypes, just have slow, giant monsters that won't knockback when you smack them. That way, you run up to them, smack their legs with your sword as many times as you can before running away from a huge telegraph attack. Like monster hunter. That will at least liven the game up as it's something minecraft would never have done before.
Also, a Jousting mechanism would be cool, such as a lance. Instead of swinging it, you just hold it in front of you and run into things to cause damage. Give it a bit more range than a sword, otherwise you'll end up next to a sissling creeper when you wanted to skewer it instead.
Thirdly, keep it simple and use DSS:MM. Anyone can create it so long as they keep the title and give me credit for the idea