Training grounds overhaul
At present training grounds is pointless after 4 victories and offers only 100 runes per victory (plus rewards). I think that the runes per victory should be scaled based on a player's tier and exceed the heroic story mode 250 since they are more challenging. I am accustomed to grinding on games but heroic story mode as the fastest source of runes gets very boring very fast and making training grounds a better substitute would make the game more enjoyable. Another idea could be the runes per victory increase the higher the amount of victories you have, also could make it ranked with a leaderboard and let it run for a week giving out rewards based on leaderboard finish.