I actually like the new translucent ones used on the LE Transformers but I would change the others to metal if i had the plain black plastic.
You're right though, it doesn't seem to affect game play, it just feels a bit cheap.
I don't blame Stern though, just trying to save a few bucks so they can keep making pins.

I'd be interested to know if anyone has had a problem with the plastic ones cracking or breaking.