The thing is, games where resurrection and/or healing are limited are advertised as such. The players know what they're in for, and this sometimes requires designing your character appropriately.
It also depends on their play style up to now. If they die sometimes, forbidding resurrection can cause them to feel as though they are being punished for saving the world. If they haven't died at all, there will probably not be a problem though. You might still have to take more care when designing encounters.
Whatever you decide though, you have to discuss it with the players beforehand. The game is meant to be fun, after all; if they don't like the idea, you shouldn't do it. You should also tell them what you plan for them to do if one of their characters dies. Do they roll up a new character? What level? etc.
Some ideas to 'soften the blow':
- Increase the number of negative hit points characters can take before dying.
- Grant them a bonus on saving throws vs dying or effects that can kill them.
- Possibly add another 'dying' stage where characters cannot regain any hit points, and only a ritual of some sort can save them.
- If a character dies, he or she can be resurrected, but only through a quest of some sort.
I don't think you should phase out dying completely though. That sounds a little boring.
It is apparent that you are facing multiple issues here. I will try to address them individually. But first:
Get everyone on the same page
You all evidently have different expectations of play, the game has a few levels of agreement that have to be acceptable to all players, the social contract, and choice of game, and the story of the game are just three examples.
You can use The Same Page Tool - It can help your group discuss and define what you are expecting to get out of the game, an excerpt from the link:
Functional play depends on everyone playing the same game. Sadly, many
people don’t even know or negotiate what that means, and a lot of game
texts leave crucial things out. Too often, people come with different
ideas and don’t realize it, and it turns into a mess during play.
So, this tool is designed to clear that all up before you start
playing.
After you have figured out what your expectations are - you can start thinking about what world to play your game in. There are a few options available to make it so that anyone could GM those worlds.
1. Choose a world you all know.
Choosing a world you all know (like Middle Earth, or Narnia, or even a historical period) is pretty straightforward, but you should make sure that everyone has about the same level of knowledge about that world, or that it is easily accessible.
2. Create a world together.
You can do this on your own - or you can use a cool minigame designed just for this like Dawn of Worlds which puts everyone in the role of a god-like creator taking turns designing and building a world and giving it a basic history, excerpt:
It was the product of many minds playing off one-another over the
centuries. The solution to our dilemma seemed only natural, we would
create a world together. Everyone would have a hand in it, everyone
would know its history.
We would become the gods of our own fantasy world. We would raise it
up from the meager foundations of stone and water. We would raise up
great civilizations, set them at war, guide them in science and magic,
and give them leaders. And we would do it in about six hours. From
this singular idea arose the game which you now see before you.
Once you have that - the decision of who will be the GM is something that I can propose two methods for, but I am sure others exist.
1. Choose a GM each session, and every player also has a PC
In this manner, the GM role is a "hot seat" players taking turns playing the GM and their own characters the rest of the time. This is a bit tricky if you are doing long campaigns, but for sessions of a few hours with smaller adventures this could be really fun.
2. Take turns running adventures in the same story
Every GM will play out their adventures and then switch out with another player at the end. You could also keep the PC's stories perpetual, just switching out one character and adding another they might meet on their travels - this keeps the players vested in their characters and also provides for some interesting stories.
Best Answer
Frankly,
Do it with skill checks and keep it out of combat, there is no combat mechanic for controlling an army because 4e is dependent heavily on the action economy that would break hard by giving a PC multiple undead allies with their own actions.
Basically, the tactical combat play in 4e is reliant on balance, and what your proposing will break the balance, hard.
However, let's talk about the skill check option here. What your opening up is the potential for a couple of sessions of largely narrative play. It will primarily involve skill checks and challenges and is a huge opportunity for your players to embrace the role playing aspects that 4e does actually do quite well.
However, for this, you're going to have to throw the combat aspects of the rule book out the window and go with your imagination and story telling aspects. There are explicit not rules for this (intentionally so), instead there is the skill system, which you can use to support the narrative play that is called for here. So develop some skill challenges that fit and have a good idea of a couple of different plot threads that you could take and then see where your players and rolls take you.
If you want the actual mechanical guts of this: the sword provides the location of the ritual (make it up) and a short skill challenge with religion checks (easy DCs) should get him a decent army depending on his checks, after that, what he does with it should be a series of narrative cut scenes, your end goal should be to advance the character, but if you want to continue the game as a traditional 4e exercise you've got to get him back to just being him.