There\'s a lot of content in this game, namely heroes, that go totally underutilized. Not even just breezed over, people are out-right avoiding purchasing sub-ruby tavern heroes because they\'re a waste of resources.
This is because their training progression is hard-capped by level bracket, and no amount of other compensation they invest will overcome that gross inadequacy, as the same amount of investment in a higher tier hero will always return better results.
Much of the diversity this game implies by their presence, goes wholly down the drain by the fact that they are rendered objectively useless the moment the player breaks into the next bracket. Not unlike Angels, who had and still suffer from this problem, but Tavern Heroes still lack evolution tokens and there is no incentives to even collect them (no equivalent to unbreakable bonds, or covenants).
I suggest you add some system in to allow players who are dedicated to their heroes to uncap those hero\'s training so they can be competitive with higher tier Tavern Heroes (see my example below on how this might work without changing the game balance). After all, much of the strategy in this game is taking what we\'re given and using it efficient ways. Once content is created that is objectively useless from the moment its release (or has been since the moment the game\'s release) you the dev have effectively wasted your time adding filler, and the player\'s time is also wasted as it is content that will never be utilized.
These poor heroes have it so bad, an overwhelming majority of the players don\'t even wasted resources buying them because they\'re just going to be tossed in 10-20 levels anyway.
It\'d be really nice if we had the option to mix, and match, and experiment with everything that\'s been created instead of just looking at the latest thing with the biggest price tag that was put out because the first things didn\'t even sell.
This would be your opportunity to really capitalize on all the heroes, heroes you\'ve already created, and not have to spend manpower and money just creating new ones.
After reviewing other features of the game, it\'s fair to say the most realistic (and easiest) approach would probably be hero-mastery tokens that work by Tavern Recruitment Tear. Once the hero is purchased, such a token could bump that hero up an Inheritance Tier, and it\'s Training Cap up the same degree.
For example: Mermaid could be \'token-boosted\' up to garnet tear, and gain inheritance from other garnet tier heroes such as Blue Mage, while having Garnet Tier training availability. Then again to Topaz, and Ruby tier with the same results and limitations. Such a system could maintain the current tier balance, while still providing long-term investment options for players to financially incentivize multi-tier, or \'generational\' parties.