I read in an article lurking on the Web that the BoC plans on releasing new banknote series every seven years instead of 15. If a new banknote series was to be launched in 2011, there would have to be another in 2018. But with five denominations currently in circulation, it may be a bit too intense to issue all five denominations in such short time frame, since the last new banknote may occur shortly before the next series would be released.
And although the latest $10 bill was upgraded in 2005, it is still basically the same as the 2001 issue - only with additional security features in lieu of the golden maple leaves. Releasing all five denominations within such short time frame may be a bit intense (besides, the Journey series was pretty much complete within 3 to 4 years of the series launch), so I can see our $10 bill heading to "currency heaven" by 2012 or 2013.
Another indicator that our $10 bill may go the way of the dinosaur is the prefix that will follow BTZ or FTZ. If the BoC decides to recycle a formerly-retired denominational letter (only A, B, C, F, G, and U remain), that means the $10 bill is likely to linger on for another few years. If they go back to the earliest denominational letter (that being "D") and release CDA or GDA after BTZ or FTZ respectively, that may possibly mean the demise of our $10 bill may be nearing us.
And besides, if they were planning on retiring the $10 bill from circulation, what would be the point of recycling a denominational letter? That recycled denominational letter would end up originally on the $2 bill, then the $10 bill, and eventually a third denomination. It would be kind of pointless to do so, IMO.