I find the naysayer's comments to be quite entertaining....
I expect it to be to the 70D, like the 7D was to the 60D. Better AF, better sealing, a bit faster, and about twice the price. Anything more will be a bonus.
Since my 60D is getting long in the tooth, for me the time is right for an upgrade.
But, I suspect it'll be either another 18-55 type cheap kit lens, or a hyperzoom like the 18-135 or 18-200.
May be an 18-200, but not another 18-55 or 18-135.
They were both released recently in their STM forms within the last 2 years.
The 18-55 and 18-135 are both very good, I really don't think they need replacement.
A new 17-55 STM would be interesting but I am wondering about the durability of the STM motors compared to USM. If a lens that sells for $300 goes bad it is not too big a deal but most photographers who buy a $1K lens for a crop camera will have it as their one good lens and if that goes bad after a couple of years of use it would be disapointing especially since Canon only gives 1 year for its warranty.
Just to throw this out there... If Dual pixel tech is ever going to hit full frame cameras like the 5d4 or 6d2 or 4d then FF will need a compatable STM lens too.