The community manager for the Polish version showed off Pipp's abilities, which are quite new. Of course, the information ceased to be exclusive after a nanosecond. Well, he likes to read and gain experience.
It's probably too early to judge the heroes. But I feel that Pipp will be relatively useless, like Kinkeria. Although, he might turn out like Wingael in the fifth game.
1. The amount of experience required to reach the next level often grows exponentially. Often, it's approximately twice as much with each level. As a result, to level up, you need to gain approximately the same amount of experience as you already have. And skills/specializations give +20%, +30%, or in the worst case, +10%. This doesn't even give you a level, not even close.
2. If you were given an extra level, would it be worth it, considering that you're sacrificing a specialization or skill slot for virtually nothing? Most of the time, no. An extra level is +1 to one stat and +1 skill for the hero, which doesn't compensate.
In reality, the only skill of this type that I remember working well is education in Heroes 5, and only because it also gives a lot of stats, not just experience. Since stats are given per level, the bonus to experience synergizes with them a little bit (but not as much as it seems; it could have been removed).
As a result, I'm skeptical about Pippin. He needs to be given +100%, or even +150% to experience, to be competitive, which the developers are unlikely to do.