Driddle said:
It amuses me that there's still some talk of playtesting the classes and deciding the final picks for the core PHB, when the UK Amazon.com site is offering a race/class preview book for sale by Dec. 17. Doesn't that pretty much imply that the big decisions should have already been made by now?
From comments (about the Ranger killed the Scout and taking his stuff, and about the Warlock being in the PHB1), it sounds like early in development they had a conversation about which classes (out of all books in 3.5) they wanted in 4e. It was decided that Scout was too much like Ranger to be a separate class and Warlock was deemed so popular it needed to be in for sure (no comments have been made about the rest, so who knows what their status is).
It seems that they started development on ALL the 3.5e PHB classes, the Warlock, and developed at least one new one (Warlord). I'm guessing that at some point it was decided that no more than 8 classes would be in the PHB1. At that time, they probably took a look at how far development was along on all the classes and prioritized finishing them based on how much time they had left and the popularity of the classes.
My best guess is that:
-Bard didn't have an established niche(they are a leader, but their ability to do so is less powerful than a Cleric, or they are a striker who isn't as good at it as a fighter or rogue is), so was going to be harder to create powers for them in 4e(you'd have to replace almost all their abilities rather than convert over the old ones)
-Monk was considered to be without a truly established niche(are they a striker, a defender, or a controller?) and less popular than other classes
-Barbarian was considered so similar to Fighter that it needed an overhaul and new defining characteristics
-Druid was consider the class with too many things it could do and therefore hard to balance as well(they are a defender, striker, leader, AND controller) and needed a lot of thought and changes to balance them in the new system
-Sorcerer was likely found to be too close to Wizard and needed a way to tell them apart and therefore a major redesign of the Sorcerer.
I imagine that Cleric and Wizard posed similar problems to the Druid, but they were some of THE defining classes in D&D and had time specifically put aside to fix them.
The rest of the classes are fairly easy to come up with narrow, established roles for and that's why they got put into the PHB1.
The PHB isn't in its final draft until October 5th from what we've been told. I imagine that the reason there was a lot of last minute discussion about what classes would be in the PHB1 is that they have mostly finished versions of one or all of the Bard, Barbarian, Druid, Monk, and Sorcerer. So, if they wanted to, they could have replaced any of the classes that were in with any of those that were far enough along.