Hakazu:
That will be a problem to solve, after all it's not fun to see one's characters die all the time
Well, don't generalize this too hard. That depends a lot on the kind of game and what the players are bought into.
Players in a Halo game would really have to understand what Halo is like.
Lots of people die in Halo stories. Ships-full, fleets-full, cities-full, planets-full, galaxies-full. All but one of the Spartan-IIs died.
The focus for a game, I think, would have to be on
meaningful death. It's one thing to play Marines who are on their butts in their ship when it takes a plasma bolt, but it's another to play Marines whose ship makes a suicide run to make sure they're able to make an insertion to a Covenant cruiser in order to capture it or destroy it. The Marines might be killed to the last person, but even then they can still trigger the overload. Their deaths would still have had meaning. Or, maybe they fail, and the next group of characters starts out being briefed on this, because that failure sets up their next mission.
Hakazu:
and creating a new one takes a long time.
That's a solved problem, as long as everyone is ready to be on-board with it.
For one thing, while characters in Halo have different personalities, they usually don't have hugely different skill sets. There could be a set number of different characters (Marine, pilot, tech, etc.) and a single pre-generated character sheet for each. When one dies, the player gets handed another one to name, and figure out a basic personality for. There'd be little reason to go in depth, since they wouldn't be expected to last long.
Anyway, I'm still up for playing. I've played Savage Worlds and it hasn't impressed me, but I'm not opposed to it, if there is a free set of the basic rules available.