As a player primarly playing in evil factions, I've noticed that wargs tend to be pretty much useless as both mounts and hired units. So, I suggest just a little bit of a buff for them.
First of all, warg health should be increased from between 18 and 40 to between 30 and 40. Why? Because such low health just doesn't make sense compared to the health of some other mobs. Lions, which are actually supposed to be much smaller animals, already have 40 health (in this mod tho, they appear to be around the same size for some reason..). Increasing hit points would also make them a bit more useful for combat, since while playing Durin's folk I noticed that warg invasions are ridiculously easy to defeat compared to any other invasions.
Second, their speed. All the wargs except for some Gundabad wargs, tend to be useless as mounts since their speed is so slow. Even for Gundabad wargs, finding one which could even get close to a swift horse or a rhino, is very difficult. So, I suggest, that their speed as mounts is increased. Gundabad wargs should be somewhere around Rohirric horses (after all, they are supposed to outrun you..) and the other faction wargs shouldn't be the speed of a giraffe.
Last, but not the least, wargs should be able to jump while mounted. They clearly can jump while not mounted, I constantly see them trying to hump walls and other things that get in their way. They definitly did jump in the movies and pretty sure that so did they in the books. Their jump wouldn't be as impressive as horses of Rohan, but 2-3 blocks of jump height would already make them way more useful.