Runic Affinity on ARAM

For all the difference it makes (I know, it's "only ARAM"), but can we either have this mastery automatically substituted for Secret Stash on Howling Abyss or give Runic Affinity an additional effect? Maybe "Health Relic restore an additional 20% health and mana over 5 seconds.", something that could also work on Twisted Treeline and Crystal Scar, or maybe something more specific for that map.