I was in the same position as you last spring when the rumors of the T4i were flying. I had bought a T3i in a nice two lens bundle at Costco and thought why not wait and see how they improved the T4i since it was supposed to be released at any time.
First of all, it seemed to take
forever for the release. Then, I felt compelled to read all the reviews to see if the new camera was worthy of all my barely contained patience. Although some thought the T3i had better IQ, and the new autofocus wasn't
quite living up to the hype, most of the reviews were positive, especially about the feared touchscreen.
One thing most people were really disappointed in, though, was the T4i used basically the same sensor (with the tweak for AF) as the T3i and 60D. Most people, including myself, hoped we'd get something more along the lines of the sensor in the Nikon 5200.
Now, I gotta believe the new T5i, whenever it finally
does come out, will have a new sensor. It HAS to

. The thing is, will it live up the the build up of hype? Gotta wait till someone has one.
If you can wait, I would. If the new sensor is a big, or medium improvement,
and Canon didn't take away any great features from the T4i, you'll be glad you waited. If not, pick up the T4i cheaper.