I am a new player, and I just found out the hard way that the Warhorse Training skill requires the Cavalry PvP skill line to actually be able to train warhorses. This is nonsensical to me from a game design perspective. Warhorse Training is the only PvE skill that is wholly dependent upon a PvP skill in order to function. Why would a dependency such as this be thought of as a good idea? As I see it, this does nothing but limit the player's choices in terms of what skills a character is built with.
Now that I've spent weeks leveling up my Ranger skill line under PvP, and weeks leveling up the Hunting skill line in PvE, I'm forced to make a frustrating and upsetting choice. Either I have to choose to give up on Ranger, which is the class I enjoy in PvP, and be forced to play Lancer in order to do Warhorse Training - or I must give up on the entire Hunting line, which is also what I enjoy doing, and do something else for PvE. Or for the third option, I can choose to keep my points in Ranger and Hunting as they are and just accept that my character will be forever gimped. No matter the choice, I have wasted weeks of my time. To make matters worse, no warning about this restriction was given on the in-game skill tree menus, and even the wiki doesn't state it clearly. Not to mention that Warhorse Training is the last skill in the line, which guarantees that anyone who does the same as me will also waste weeks of time.
My suggestion: allow characters that have sufficiently high Warhorse Training to ride a warhorse while training it, regardless of their Cavalry skill. When the training is completed or fails, immediately kick the character off the warhorse. If you are worried about players exploiting this for battle, measures can be taken to prevent that. For example, if a character takes damage while riding a warhorse that they are training, immediately kick them off the warhorse. In addition, limit the radius a player can travel from the Training Field before they are kicked off the warhorse.
I hope this feedback is taken under serious consideration, because this unfortunate situation has significantly ruined the game's appeal for me.