You see I have no issue with Pandora, She's a solid debuffed, control model. Excelent, really enjoy playing her, always a challenge but I never feel I can't beat her.
Then you get to Hamelin, now I have no issue with him being a controller, creating swarms of rats, making the opponents model insignificant. These all feel like they are things he should do. The real issue I have is he can do SO much more than this.
Hamelin is fast, has fate is meaningless and a really high Serious damage. So you manage to fight your way through the rodent horde to get to him and he can practically one shot you in melee. I have seen games where Hamelin has run off on his own and killed Avatar Ramos, the Mechanical Rider and a Arachnid Swarm single handed in melee.
Hamelin can come back indefinitely, which means he is also much tougher than a lot of support masters, and too be honest he's not even that easy to kill once.
On top of that due to the way the swarm works, he can really slow down the game. How many times have I seen one rat get killed which creates another rat that kills the first rat, just to run out activations.
So yeah I feel Hamelin needs a bit of a fix. But no, it isn't because he's a Debuffer/Control model. It's because he's a Debuffer/Control model that can hit as hard as McMourning and is as tough as Leveticus.