My feedback on the ideas here:
1: Their corpse doesn't simply get back up again. Not out of the same context as the rest of the world, anyhow, from what we've read so far. A person still has to spirit walk. Still has to find their body. And still has to deal with any penalties SbS chooses to attach to resurrection, along with possibly having had their weapon (at least) and armour looted, rendering them useless to combat until they can acquire another.
2: Bloodlust, as Labbe's pointed out in another thread, is simply a temporary bar on spirit loss after one's first death. It's not a new mechanic, they've talked about it in the past as a means of ensuring that griefers can't destroy people's sparks by repeatedly killing them and warriors at war aren't burning through entire sparks in the course of a few battles. It changes nothing about combat except for ensuring that securing the field is as important as actually being able to defeat the enemy.
3: Combat "lives" will be softcapped with SbS's existing mechanic. If it takes progressively longer to get back up after dying - even accounting for spirit walk time, into which we have to factor fame for anyone who isn't a nameless nobody - people are eventually going to be waiting for a decent amount of time to be able to resurrect, and on a field of battle, getting up straight away without your section of the field being secured is going to be extremely dangerous, with or without resurrection penalties. I don't feel this needs adjustment. It just needs an appropriately long resurrection delay for successive deaths, with the death mechanic for not entering one's body during spirit walks suspended once the corpse is actually found so you're not just ebbing into nothingness because you happen to have died a few times recently in combat.
4: I like the first half of this, and feel that morale and command bonuses would be excellent additions to the warfare system.
5: Not sure how I feel about this one. Would we even have our gear in the astral plane? Would we be able to encounter other souls? If so, would interaction be possible? We know next to nothing about spirit walking at this stage, but I don't think it would make sense to be able to fight in the spirit world. Not unless there's predatory entities roaming it that need to be fought off in the course of a spirit walk, which could be interesting play... if a bit harsh on players who don't know what they're doing.
Personally the only thing I'd really want changed is for staged battles to simply operate as normal combat, with the exception of the battle table being involved for command purposes. Combat doesn't need training wheels or extra scaffolding. We don't need additional objectives; the goal is the goal of whoever leads the force, and that's all that's really needed to make it a battle.