Why do you assume that if someone wants to use a image, something has to wrong with words?
Icons have replaced plain-text at a lot of places. The browser that I am using (and probably on your browser too), icons would have replaced: Back, Forward, Refresh. Probably because they save space or probably because they are language independent. Of course, one might have to hover on them for a second to realize what they do, the first time you try them - but next time onwards, those with a decent memory (and I am telling a limitation of icons, not discarding importance of those with poor memory), can remember what they are meant to do even when they use much lesser screen space.
The central question is that what is wrong with images (and now an option to change them to text) if it is serving a much larger audience or serving the same audience better? And at what point did it became Gmail team vs Gmail users? "Haha, they lose because they gave us the option we wanted". Mind you, for each one of us who demand something, there probably are thousands who either don't care or like the new interface. Even at this thread, I can see two people using comfortable white-space setting. Even I hated the change from classic themes to Compact; now I am comfortable. Since when did we become to averse to change?
I think you misinterpreted my response. When you ask the question "What is wrong with words?" in conjuncture with "X should be text based"; you are either genuinely asking for a reason for why would a designer chose images instead of text or you are being sarcastic.
I assumed you were genuinely asking the question; because assuming sarcasm would have meant it was more or less useless for the thread. Hence, I pointed out both pros and cons of using image icons. Additionally I was also replying to the root comment and to those who were agreeing to the sentiment.
What is wrong with words?