Wintersong, this is the kind of discussion I want!!
Tactical/Strategic Stack Undo: What if the square (or whatever) is already occupied or is not "accesible" anymore? You are only time moving one unit, not the whole board.
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This is a kin observation; just make it a requirement that the tile has to accessible before the "Stack Undo" can be casted. This is really cool spell. When you have enough essence or mana to cast it, you can essentially send your stack as "bait" to damage your opponent as much as possible in one round. In the next round, you cast the Stack Undo your unit will be back to full health while your opponent is damaged.
A new "Bait" category of spell in either cloth map or battle.
Tactical/Strategic Stack TimeTravel: I seem to fail translating this one. So I send Unit A to Limbo for 3 turns. In "real time" that would mean 6 turns for the other units. Why not match the turns in limbo&real time?
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For example, if your opponent stack is poisoned & is expected to die in 6 normal turns, you send it to the limbo to make sure it will die from poisoning. Because time runs doubly faster in limbo, his stack die in the limbo after 3 turns instead. Your opponent has no way to summon him back from limbo (unless there are some ‘limbo-summon’ spell). In my version of limbo, it is a special plane that time goes way faster (it comes from some Chinese myth). This 'clock run faster here' concept is just something I add to jazz up the fun.
Strategic Equipment TimeTravel: Ok, this is planar travel and not time travel. This Limbo can have a different time synchrony than the game world, so sending one armour to the nearest city through normal means could take 20 turns but through the Limbo just 5. But it's still planar travel. I do like it tough.
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The extra plane is something many of us want. If this plane also has a different synchrony from the game world, it would certainly make it more interesting. This plane would be just a limbo to use as road (or it wouldn't be possible to have such time difference without serious headaches and turn managements). As such, it would be used for allowing faster trade/movement. It wouldn't mean insant travel as unit would take some time to reach theirs destination. Problem is that units sent into the limbo during strategic part of the game, could need food too?
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The limbo I've talked about is not about "Planar travel" (but planar travel can be cool too). AWOM:SM has a shadow world that doubles all units' movement speed, it is fun but not really great (it just feel like another speedier version of underground map layer, for many players point of view). In this version of Limbo, it is more like a 1 tile cloth map. You can send your equipment there from anywhere, you can send your troop from anywhere. But when you exit this 1 tile map, your troop returns to the exact same location from where it come from (the same turn or many turns later). I am trying to present some kind of alternative reality in the Limbo here.
Planar travel may be cool, but so far I cannot think of something that is different from AOWSM & fun at the same time.
Battle Redo: .... To be balanced it should be just right after the battle ...
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I agree that the Battle Redo has to be done, right after a battle. Otherwise probably there are quite some confusion will happens, namely the butterfly effect.
Diplomacy Undo...
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Initially I was thinking about, maybe your opponent is doing something bad to you, you Undo their diplo efforts using this Diplo Undo spell. After you undo their diplo action, you can aggressively take you diplo actions now so that when next turn arrives, your opponent may not be able to repeat whatever they had tried to you before.
Limbo: I get the feeling that it has very few to do with time travel and is nothing but an extra plane. I like extra plane. But... I send a unit to Limbo while in battle. Previously to that I had sent some merchants with armours through Limbo. Err... bye bye merchants and armours? If that plane is so tiny that they must fight until there is only one. But if you can have any number of your units there, why not allies? (backstabbing allies doesn't count)
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I understand what you meant. Yes, probably you can send any number of allies to the Limbo and exit safely altogether. The 'only one can exit' rule is just a means to have an interesting way to represent risk to time travel.
Time travelling is like... uf. If you can redo a battle, why not the last quest you failed? Or as I mentioned, the last turn? Things that involve back in time are bad (altough I liked the Diplomacy redo). Jumping into the future is a quite different beast tough. "Dear Paladin-Captain Leonard, we are low on food so I'm going to send your Paladin unit 20 turns into the future. Hopefully, that will allow us to save some money and food. And maybe when you appear we can afford to keep you guys around. All that for the affordable cost of 100 mana and 5 Essence."
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Maybe troops in limbo don't/can't eat & don't get paid? Suffer morale problem after a while spent in limbo?
Any time travel related spells require careful balancing and playtest & most of them are powerful so you’ll see only at end games (or if your Sovereign specialize in it). I am just excited it can provide an extra dimension to all-so-familiar spell system everyone is talking in this forum.