I suggest that Guard Towers should be added to our Bastions.  They should be something that we can unlock like the gem mine or the sparring pit.  Once a Tower is unlocked it could be manned by a level 40 or higher champ with an aura skill.  Six items of level 12 gear could also be required for the champ.   Once the champ is stationed in the tower he would no longer be available for any other use.   10% of the aura skill would then be added to every battle.   The rules governing the aura skill would still apply so a dungeons only aura would still only work in the dungeons and so on.   Players could then unlock a second level of the Tower which would require a level 50 champ with 8 level 12 gear items.  The benefits of the level two Tower would provide 25% of the champs aura skill across all applicable battles.   A third Tower level would require a level 60 champ with 9 maxed gear items and boost the aura to 50% of the skill.

The players could build up to six Towers, but only one type of aura could be applied by the Guard Towers.  The expense of building and manning the Towers would keep them as a tool that only long term players would get.   It is unlikely that players would develop champs solely for use in the Towers, but rather as a place to use their old aura champs that would otherwise just sit in a vault.  

 I also think that it would benefit the game to add an Aura Block skill to some champs.   These champs would cast a debuff that blocks the effects of all auras on the target champ for a set number of turns.  Giving this Aura Block skill to some of the weaker Legends and Epics could be a way to balance them with their mightier counterparts.  It would also add new strategies to the higher level battles and keep the Guard Towers from becoming unbeatable.

I believe these additions would help extend players’ interest in the game.   The Towers would be unlocked like existing game content and the aura would be applied in much the same way as Great Hall Bonuses, so the challenge to your developers should be modest.

Thanks for your consideration!