“Wow! Beyond Hero level 100! That’s awesome! Have a free Gem Key and some Gold!” (Pictures of 1 gems key and 1000 gold )
Something like this could be in your Mail as a reward to award the hero level beyond 100 like you have it with the Hero levels beyond 1000.
If doable (and they actually counted the experience gain in the background), I would suggest to level up the Heroes across accounts and reward them accordingly.
If not… What a shame! You never drop any game data even if you don’t use it at this time.
But what can you do…
What do you think?