We'll just see how the new hero turn out to be, then we can simply complain here just as usual if it turns out to be too weak/strong
I actually disagree. I feel that this is the perfect time to voice out the complaints, and the perfect time for the developers to give their reasonings. Fixing a unit after it is made is always more troublesome than fixing a unit during development.
What the devs failed is that they did not provide us with an example of the unit. The arena hero change was perfect because they gave us examples and we know what kind of changes they would cause. With that, we can then instantly see the problems with such a change. As such, the devs can then review their changes better.
In this case, we got a vague (on spawn with rng). This caused a stupid amount of unneeded speculation and no clear way to give good opinions, suggest something useful, or even give clear problems with such a mechanic.
This should be enough, but I'll give an example too.
On spawn skill(Activates every wave): 60% chance to increase Crit to 100% and Atk by 30%, but silences self for 2 turns
Do you think you can give a better opinion and review from looking at the example above, conpared to what is written by the devs now?
Bonus edit: Look at the Elves post again, and notice how more detailed it is compared to Camelot. It explains the 10-40% bonus stats, the on hit effects, and the buff removal caused by changing modes. Then look at this again.