It seems I won't be able to convince you, but I'm still on the side of the optimal choice. I think it suits my playstyle better, and it seems like it will be stronger overall. The general defense of Haven is what makes the difference... But the topic is about the weakest castle, and in my opinion, that's just a misunderstanding. There's no magic, which is terrible, even though there are many creatures. But magic is what matters, in my opinion, and playing as them is boring, with zero tactics.
In general, I consider Necropolis and Stronghold to be the weakest castles.