If the mounts can become companion like chocobo aka being able to tank, heal or dps, then this will bring the wrath of the anti-p2w club on SE. I think this will only work if they exclude the mounts from cash shop and only make mounts obtainable from the game into companions.

Which is a shame, since I love Sleipnir, its my favourite mount and would make a awsome battle companion, but I can understand why some players would not like this.