First off in the high times of Forest Guardian Entourage tons of players of all, even the top brackets switched one of the Kerberos for troops like Deathknight, Psion, or whatever else they deemed fitting all the time. So while i might agree that 2 Kerberos for that team would be optimal(my personal opinion), many other choices for the 2nd Kerberos slot were just as viable and very damn close in overall power.
Second, two Kerberi on that team work so well exactly because Forest Guardian is benefitting both of them!
Without FG xKerberos is easy to counter, keep one from filling which is really easy at 16 mana and the others won't fill ever either.
The point stands: 3 Kerberi+notFG is a joke compared to a single Kerberos+FG+2whatever.
Stacking troops here is not the root of the problem, the synergy between Kerb and FG is, stacking Kerb merely escalates it and honestly not even to that high of a degree.
Again stacking here is not the root of the problem, you actually name the root here. Stacking only escalates it.
I agree on empowered and extra turns being very powerful, but honestly without empowered Wisp loses almost any value for me, as i see it mainly as the answer to shitty starting boards, without that it is just gonna be a more expensive War Sphinx with an extra effect added to it i don't care about.
In any case we should wait and see how this troop actually Impacts the game before we cry nerf, no real harm can come from it right? Killing another troop before release though with outcries for nerfs...