I do really like the porcupine formation, I wouldn't like to see it removed. It really makes your lances the best cav-counter in your army. If they would get something similar to the Tower Guards or Pelargir Trollbenders, Gondor would have 3 lances with similar types of formations. Right now you can choose between all of them since they all do have their benefits (especially with the central spell), I would prefer it to let it stay this way.