I think if you tried to use pictures there would be a lot of, "What does that card do? Let me see the rulebook."
Yeah it happens in some games that are poorly designed but most games can do great pictograms that also have the benefit of getting rid of that language dependency problem as well!
Look at games like :
7 Wonders's special cards (yellow, white, purple and wonders)
Smallworld's special powers did a wonderful job at it too
But you are right about the fact that this would lead to the dreaded "let me look at the reference sheet" moments. I prefer that to having to consistently double check who does what by requesting them to read aloud what's written on their cards because my poor eyes can't see what's written on the table..
At the very least they can keep the text but put a distinctive picture on each card (over the text). That would make it easier no?
I understand both sides.. My intentions are not to bash that game I enjoyed a lot!