This is a suggestion.
Can you unlock the limit it has of 20? I hate having to wait to level the skills of the heroes each time I level or each time there is a new hero.
You could either unlock it to everyone or to a certain VIP level. It is just frustrating sometimes.
And this happens at all levels and to non-vip and vip users. In my another account (non-vip) I have the gold and still have to wait, now in my main I just get anxiety when waiting xD If one has the necessary gold, one should be able to use it to level abilities.
Also, if not unlock it, at least increment it to 50 or 100 xD