I totally agree.
I love Bioshock as a game and wanted to platinum it but now, i dont want to. I dont want to ruin the game with another plathrough. (I've done 4 playthroughs)
It's a great game too but the trophies were too bronzy, but maybe that was a good thing. Yeah, finish the game on hard = bronze. Find every tonic = bronze. I think it would have been annoying if it was gold and silver filled though. It would slip into a trophy whore's game and i think i wouldn't have enjoyed it as much.