Magnus may or may not be OP, but tradition tells any hero who has this kind of performance will be nerfed.

Personally, I think the whole "kidnap people at your barracks and throw them into the fountain" is perhaps too good. It's a hard combo to pull and require BKB and Blink to be made safely but this never prevented people to call stuff overpowered.

Or Icefrog may nerf Dark Seer again, who knows... the frog works in mysterious ways.