Samuel, there are very significant differences between the GLD and X32. The number of preamps is absolutely the most insignificant of all the differences. The GLD is the most flexible console that is affordable to lots of people. The x32 is the most cost effective console for basic mixing.
I'm familiar with the desks. I called it the "simplest" difference, not most significant. By that I meant that # of mic pres is a simple metric for eliminating as a purchase option - if you need 40 pres, you can forget any other features because the X32 has been eliminated.