Yes, but the t4i has to be updated compared to the t3i, else why call it the next generation of rebel? The t3i has a 3.7 fps burst rate. Is it that big of a leap to give it 6fps? It would best the new Nikon offering.
Yes, that would be a huge increase, nearly doubling the fps. It would best the 60D, the 5dII, and put itself in line with the 5dIII or 7D...which are pro bodies that sell at more than double the price.
Remember, the Ti cameras are entry level; the point of crippling them a little is that people who need features (faster fps, lower iso, weather sealing, great AF) upgrade to a line that has them. If they make the T4i better than the 60D and give it features that make it even close to the 7D, they'll have destroyed any upgrade path in the APS-C line. Who would buy a 60D if the T4i had a new sensor, did 6fps and had 19pt AF? Or a 7D for that matter? And what they'd have to upgrade the 60D/7D to to get sales back would be insane; they'd basically be an APS-C version of the 1DX, and for <$2000? Not happening.
I'd say new sensor, Digic V, little better fps (4-4.5), maybe slightly better AF system, and they'll use a variation of the video AF that Nikon has used for a while. And nobody who wants good video will use it, because the Nikon AF for video is terrible; similar to pressing the shutter button and letting it hunt. Their last update was a flip out screen, I'm not expecting miracles.