I really like the idea of 'Troubador' for Bards which is an elemental mount summoned from the spirit of many ancient battles. A horse that can help CMan Charge and snort flares. The Bard gets a nice boost to a lot of battle skills and can do a few things to help if you are down.

For Paladins, it's a natural for them because of the classic knight image. Gemstone doesn't allow knight references actually (right?) but it still would be automatic with the full plate/lance build available to Paladins. In fact that's my Paladin's build and a lot of the reason I like the horse spells but it would be awesome for any weapon base except unarmed I guess.

The spirit horse is something that I would really like to see Simu consider sculpting customization for with the Paladin. So they can go through a process to design their horses appearance. I prefer once and it's not possible without a reset but maybe changeable? I prefer it set to a God of Elanthia then having a basic similarity to their appearance with a lot of variables for color, jewelry or other godly adornments... When the Paladin mounts the spirit horse he cannot ride through towns and they will not be able to hide, there would be obvious limitations for movement through barriers in terrain, Some CMans would be unavailable.

But the advantages for battle to being on the spirit horse would be that they gain AS from the height/leverage advantage, they become less likely to hit (especially in their upper regions), the mare can assist battle with distractions, in a spirit horse would imagine not nostril flares but rather a special attack which would be more in line with something like a CS based spirit ward or BIND effect based on a manuever would be huge. Imagine the horse successfully maneuvers spontaneously and the target is BOUND from being pinned. If the Paladin happens to be trained in Charge then a big bonus would be automatic, +25 or more. Also a regeneration mana/spirit boost while mounted.