She argued that before the crusades, most of Western Europe only had wooden motte and baileys for fortifications. I found a book making a similar argument from a cursory google search, but is this a mainstream view?
UK only. Its true to that crusades had a significant impact on castle design. How could they not? They were one of the major military engagements of the period. The rise of stone is more complicated.
Stone fortifications did already exist in UK. This is the Roman Portus Adurni (probably):
https://commons.wikimedia.org/wiki/File:Portchester_Castle_D_shaped_towers.JPG
other stone structures would be things like the town walls of Canterbury.
Castle building in the UK really gets going with the normal invasion of 1066. The early castles were yes wooden Motte-and-bailey (although Motteless bailey and baileyless Mottes were constructed). However stone structures appear fairly quickly in the form of gatehouses and the like. A few were built in stone before the first crusade such as Peveril Castle. Others such as Norwich Castle had stone keeps added at about the same time period.
Wooden castles have a lot of advantages. They could be built quickly in an often hostile country and didn't require so many skilled masons. They also work well with the Motte-and-bailey design. Unless the Motte is a natural hillock it will be made up ground tend to settle over the years causing subsidence which is less of an issue for a wooden building (its not clear if this was understood at the time).
As the wooden castles wore out they tended to be abandoned or replaced by stone. The time the motte in these structures had had to settle meant that subsidence was less of an issue.
The next big drive for castle building in England was The Anarchy (a 12th century civil war). You see a lot of very rapid castle building (including Siege castles) which tends to favour wood. With the end of the anarchy the continual movement in favour of stone continues and the crusader influence becomes more of a factor.
One thing to remember is that with castles general trends are just that general trends. Designers and builders were in most cases responding to local conditions and geography which drove their designs.
Sources
M W Thompson's The Rise of the Castle,
Stafford Castle Survey, Excavation and Research 1978-1998 Volume II The excavations (which covers why the thing stayed wooden for so long and why the excavations were so disapointing).
