Why is a recurring fee even necessary? Don't get me wrong, I wouldn't turn a fee down if someone offered me it but it doesn't seem like it's essential for doing something that requires no effort once it's been set up
It would make sense if it's some sort of insurance fee: in case the forum's funds are lost, the treasurer has to pay for it out of his own pocket.
However, that only makes sense if the treasurer holds enough coins on his own to
easily be able to do that. I read the requirement when theymos was looking for treasurers: they had to have handled much more than the amount they would hold for the forum, but that's also at a time it was worth 99% less in dollar.
Alternatively and to rule out any shenanigans, maybe it's better for thyemos to just hold the money himself in maybe a safe deposit box and get some sort of legal contract drawn up in case of his death (or whatever) that the money will then be sent to certain trustees or to certain trustees multisig walllets.
Isn't a published signed transaction that can't be broadcasted before (say) block 750,000 a nicer solution than a legal contract? That only requires to move the funds every 150,000 blocks or so.