i'm sick and tired of reading how IS would make a lens so much heavier and biggerand compromise image quality ... bla bla bla ... just a bunch of completely unfounded urban myths.
e.g. look at EF 70-200/4 L without IS 76x172mm, 705g and EF 70-200/4 L IS with IS 76x172mm, 760 g ... so a paltry 55 grams more .. for a lens with pretty big glass elements to be stabilized. And image quality is better on 70-200/4 with IS too. Price difference is excessive though, and purely marketing driven.
EF 24-70/2.8 L II should have been IS from the start ... especially at the price differential over the previous version.
They shot to just about the limit on pricing with the non-IS ver.2 at a whopping $2,300.00. That is the same price as the 70-200 2.8 IS ver.2. (Which of course DOES have IS.). They left no realistic pricing room above it at the top for an IS version. If they do release an IS version, so as to match the multiple flavors in which the 70-200's are offered, they can't price the thing any higher than that. They will have to dramatically lower the hefty price of the non-IS to make room for it. I assume that would pi$$ off some of the folks who paid full price.