Hydromancerx
C2C Modder
I think big cats would be a little stronger (by about a pt margin) than an equivalent dog unit but unable to spot stealth units like a dog but unlike a dog can BE a stealth unit (that can't plunder). I also think they'd be very good with withdrawal and speed (overland movement) but should not gain any defensive bonuses (thus that tree climbing would be thus better applied as an attack benefit.)
They'd also cost a bit more than dogs to maintain thanks to the large investment in food that would be necessary to support them.
In short, they'd be the Rogue of the trained animal line. (though they wouldn't spread crime...) Perhaps they should also have the assassin's specialty of being able to target particular unit combat classes in a stack, with Canines as their primary target - useful in taking out the enemies that can normally see invisible units.
That's more or less what I was thinking.