It would be nice if the buff time got increased from 5 minutes to 10 or even 15, since it has no cd time, and just increase the mana cost value to go with the time extension. Becomes a pain having to recast it mid battle while trying not to die lol.
Suggested values of mana cost:
10 mins buff 800mp or 2% mp and 385mp
15 mins buff 1150mp or 5% mp and 385mp