To keep things fun and random, especially for late game players, I would love to see a “modifier mode” applicable to all battle types. Basically, for a gold fee you could enable this mode, with a buff to rewards if you win. All of the mods come in groups, and only one from each group can be randomly selected (up to 3 mods can apply). Some will accelerate the battle, some will slow it down, and some will just make it…different.
Some example mod groups:
All troops start Empowered
All troops start Diseased
All troops start Fast
All troops start Entangled
Both banners apply to both sides
Both banners do nothing
Jumble mana amounts required within a team
Jumble mana colors required within a team
All troops using [color] gain [1-2] [stat] per turn
All troops using [color] lose [1-2] [stat] per turn
All troops gain 1 mana per turn
All troops lose 1 mana per turn unless full
Double effectiveness of all traits
Halve effectiveness of all traits
All troops have all traits enabled
Traits are all disabled
[color] mana appears twice as often
[color] mana appears half as often
Battle rewards doubled
Battle rewards halved