From 1988 to 1993 I was one of those 'greeks"* that was in the photography/year book club in highschool.....
Back then, we had to get the final layout off to the printers by March 13 (first day of spring break) IF we wanted the book for June 21 the second to last day of school. That usually meant the yearbook club pulling 6 to 7 hours a day AFTER SCHOOL. for about two weeks to get all the last minute changes in.
Adding a sentence, or changing a caption is a BIG deal as it can throw the flow and continuity of a book all out of whack. Meaning, that adding a sentence is not a simple matter of sitting down and typing in a sentence... It's typing in that sentence, THEN checking every single page afterwards for the errors created by adding in that sentence... and then correcting them, which can end up costing you hundreds of man hours, and then several dollars more at the printer due to adding volume to the book, extra pictures to fill in blank spacing, blank pages, etc...
Yes technology has changed a whole lot since highschool. (back then, you were "cool" if you had a Walkman and a cordless phone in your room....and forget about a computer... they were $5000+!!) but the simple fact remains that is cost big money to reprint a massive book when they could to a printed errata for a fraction of the price... or just release it as a PDF on the main webpage for free (to us)... and could keep CGL out of "panic mode" for a while.
And really, when you look at the "real" problems, and not include the whiney ones, the number of clarifications and changes is actually pretty small.
as with any time a company releases a new PnP product, use the most up to date sourcebooks and fluff combined with the new rules to flesh out the details until they can get the new errata and sourcebooks out. And above all remember the 3 golden rules:
1: If something seems to powerful, you are probably missing or overlooking something.
2: RAW and RAI can be two different things... figure out which way you want to go, and stick with it throughout a campaign, if your wiffle back and forth, the chances are great you are going to "break" your game and be a very unhappy (whiny) poster.
3: Common sense rules the day! Use your common sense to problems that creep up and move on. If you don't have common sense, FIND SOME!
*(Or "that supreme asshole that just blackmailed you cause you really pissed him off" to dozens...)