Nice to see this thread's still alive & kickin'. Well, IMHO, I've got mixed feelings about this issue...
On one hand, I like most of the new core classes that I've seen so far from WotC, esp. ones that aren't really campaign-specific or too setting-specific. I wouldn't be surprised if I wind up adopting quite a few of these new core classes, as long as it's feasible to have them shoulder-to-shoulder with the existing core classes. Heck, an elf battle sorcerer sounds really close to having a character like the elf class from OD&D; doesn't really have all the weapon & armor options, but then again, it wouldn't be limited to 10 character levels & 5th-level spells.
OTOH, I think that this plethora of core classes could have been avoided by having some of the existing PHB be a bit more flexible—not necessarily as a sidebar or an option mentioned in the DMG, but actually as the base class listed in the PHB. A generalized "fighter" class that was a bit more malleable could feasibly cover other classes like the swashbuckler, samurai, thug, knight, wilderness warrior (i.e., non-spellcaster ranger), gladiator, etc. A generalized "priest" class could cover some varieties of divine spellcaster, like healers, druids, shamans, cloistered clerics, etc.
As I've stated before, a lot of this stuff is optional. But then again, that's exactly the issue—it seems that a lot of the options in Unearthed Arcana change some key mechanical aspect of the game, like how spellcasters use magic, or how skills are gained/used. In essence, having a base assumption on how things work in D&D, as well as what's possible in the game, isn't as feasible anymore. The basic premise of "How Things Work in D&D" may have to be redefined from gaming group to gaming group, which doesn't necessarily promise an easy learning environment for new players unexperienced with D&D, esp. if a new player joins a veteran group who employs their own preferred set of options/house rules in a game. It's also quite feasible that within one gaming group, how D&D works, and what's possible in D&D, will be defined by each DM who runs a game—one DM may prefer to go for as many core classes as possible, spell points, & possibly some other variant systems; another may opt for using generic classes only, Defense Bonus, and VP/WP; still another may go for basic, straight-from-the-core-books D&D.
I dunno—somehow it seems to me that a fair amount of this later revision & add-on options could have been avoided by merely accounting for it in the core rule set. For example, let’s look at the subject of this thread—core classes. A more malleable fighter class could have accommodated for different kinds of fighters, whether it’s the heavily-armored knight, the quick & agile swashbuckler, a wilderness warrior, a tribal warrior/barbarian that isn’t a berserker, the various types/fighting styles of samurai found in Oriental Adventures, etc. A more malleable rogue class could accommodate the traditional, thief-like class of D&D editions past as well as the wilderness rogue/scout, spy, more roguish swashbuckler, pirate, assassin, ninja, etc. A more malleable priest class could accommodate the classic cleric along with the cloistered scholarly priest, a druid, a shaman, healer, etc. A more malleable mage class could cover the typical wizard, along with the spontaneous sorcerer, a more battle-oriented mage, wu jen, specialist wizards, etc.
And it wouldn’t have to be reduced down to the old core 4 classes, either. Paladins could be made a bit more malleable to accommodate for paladins of all ALs (or just aspects such as good, evil, law, & chaos), & not just LG. Monks could be modified to represent the typical martial artist/unarmed combat master, & not necessarily have the monastic/religious/mystical connotations they have now, much less the Lawful ALs-only requirement. The druid class could remain separate from the cleric class, representing the more animistic/naturalistic priesthoods such as druids, shamans, & the like (leaving the cleric class to cover the more institutionalized/civilized priesthoods full of clerics, cloistered clerics, healers, etc.). The ranger class could be more malleable to cover various kinds of “hunters,” from the traditional wilderness ranger to urban rangers, bounty hunters, assassins, justicars, investigators/detectives of the city watch, etc. Bards could be adapted to cover concepts such as the urban minstrel, barbaric skald, court jester, traveling actor, cunning diplomat, gifted craftsman, etc. Barbarians could be adjusted to cover the uncivilized berserker, tough front-line shock troops, unyielding bodyguards, fearsome gladiators, rough & tough brawlers, etc.
I don’t think that the rules for core classes should necessarily go to the extreme degree that the Unearthed Arcana generic classes (Warrior, Expert, Spellcaster) propose, but they could be a bit more flexible & accommodating for various concepts out there.
I dunno—I think that part of me is concerned that D&D will wind up going down the path of Palladium RPGs/Rifts—it seems like it could by introducing more & more core classes, and even with the racial paragon classes in Unearthed Arcana and the monster classes from Savage Species. (Sound like R.C.C.s from Palladium, anyone? It's starting to for me.)
There is one thing that I'm curious about, which I'll have to wait on getting a copy of UA to answer—does UA mention what should be taken out/modified if a certain option/variant is used instead? Should a battle sorcerer replace the standard sorcerer class, or could both be in-game? Is it feasible to have domain wizards alongside standard wizards, or cloistered clerics along with regular clerics?