BigBunny
Super Freak
I've been reading some who had similar problems with having weak magnet. Well, the only solution I can think of is putting Bostik Blu-Tack or similar putty-like adhesive inside the arm slot. At least this is reusable and non-permanent, so you can still switch it with the lowered arm whenever you feel like it. Hope this helps.
that is so cheap and tacky though i don't want to have to put blu-tack in my collectible Boromir that cost me $340 to buy