The traditional way to get around this problem is to use groups of smaller CR numbers. In theory, it should break down something like:
one CR 11 creature = two CR 10 creatures = four CR 9 creatures (etc.)
Except that doesn't work with the XP budget system Pathfinder has in place, which goes like this:
one CR 11 creature = 12,800 XP
two CR 10 creatures = (2 x 9,600 =) 19,200 XP
four CR 9 creatures = (4 x 6,400 =) 25,600 XP
In order to have an encounter of four creatures with the XP budget of a CR 11 encounter, you have to make those creatures CR 7 (worth 3200 XP each). But then you run into a different problem: a CR 7 critter has an attack roll of something like +13 -- which means it's going to need to roll a 15 to hit one of my players. Because of the geometrically-improving nature of level-based play, anything worth few enough XP to fit into the encounter budget, is not likely to make much of an impact on the group!
That's the budget for an "average" encounter ... which the game suggests should constitute about half of the encounters in any given adventure. But I'm not sure how good a guideline that is when you combine it with the "try to use multiple creatures in an encounter" model. What you get is a bunch of encounters that don't really challenge the group that much. It does wear down their daily resources of course, which is the key difference between older versions of D&D and 4E, but that's for another post; but the key problem with "resource management as challenge" is that a lot of the scenario ends up feeling like "filler."
Or, to put it another way, do you remember the giant battle with the orc chieftain, the tribe adept, and their personal bodyguards, or the twelve rooms of 3-6 orcs each you came through to get there?
It's not as big a deal in low-level play because the disparity is not quite so obvious. Something dangerous to a 1st level character can still be dangerous to a 3rd level character, particularly in larger numbers. But many things that are dangerous to a 9th level character, just don't seem that dangerous to an 11th level character.
We'll see how it goes in play ... but on paper, it sure looks like "cakewalk, cakewalk, OMG boss fight!"