Seems to me that at least one potential purpose of the "next" Rebel is simply to have a "latest model" available for marketing purposes.
I'd expect most Rebels to be purchased either by people new to 'serious' photography, i.e. their first step into interchangeable lens territory, or perhaps by colleges.
For a number of first adopters (and I know a few, as I often get asked by people buying their first SLR) £250-350 is a lot of money - it's a new fridge, dishwasher, washing machine budget. For them, getting "the latest model" is an important part of the choice of what to purchase - the same reason that car manufacturers release new versions of essentially the same model every 4 years or so.
For someone making (for them) a significant consumer purchase, ensuring they buy something that will not shortly become obsolete (due to apparently being superseded - more experienced customers know it isn't actually obsolete ) really does seem to feature in their decision making. It should't matter, but it does. (Caveat: my limited experience of 'newbies' only).
If it is a new DSLR, I'd expect a refreshed model, with latest updates for features that are either as cheap, or better still cheaper, to manufacture, for the simple reason of being able to offer a "latest model" to new/future customers.