Well, let's also not pretend Disney wasn't issuing the same paper tickets up until My Magic plastic cards were introduced what.. 2 years ago?
It has never bothered me that my tickets are on regular card stock at UOR, the only inconvienance to my family (and the staff at UOR) has been how easy the bar code seems to smudge.
Back when we had Disney passes, they gave you a new one each year. UNI has you keep the same one, again, this is no big deal to me. What has been a slight inconvenience is that the passes have become unreadable at different times.
On our last trip, my daughter's pass would not scan. The person at the gate could not read the numbers so they had another team member try. He finally had to ask about my wife's and my numbers to try and guess what the last two numbers might be...this annoyed the folks behind us in line more than it bothered me.
No big deal, we went to guest services in the park. I'm not sure why I did not get mine redone, but my wife did as she said hers was having issues as well so she sort of mentioned that they needed plastic passes and the employee behind the counter said something along the lines that they would love that as well.
Anyway, I think Disney used a better card stock and me personally, I could care less about what they use...but I do think UOR would help eliminate an annoyance to guest and staff if they gave use something that did not fade or smudge so easily...I'm not one to defend Disney, but I never had one of their tickets get ruined (maybe the water rides at UOR are to blame).
Anyway, it has not happened a lot to us, but my daughter's pass has had to be redone three or four times in the time I have had two, but I got the feeling from guest services that it happens often to pass holders so change probably wouldn't hurt anything and it sounds like plastic would please a lot of folks.