So far, changes include:
Reduced to 2-column layout.
Different color choices.
Header and footer images.
Color class and monster art.
Spellchecked for American English.
New Classes: Gnome (PC2), Mountebank (Darker Dungeons).
Druids are now a full class (DRGN177).
Thief ability progression to level 14 reverted to expert set. After level 14 progresses similarly to RC.
New Skills: Snares (RC)
New Equipment: Flail (Darker Dungeons), Kite Shield (GAZ15), Morning Star (Darker Dungeons), Small Shield (GAZ15), Tower Shield (GAZ15)
Elves have a new spell list, with some new spells (GAZ5).
Some spells now function differently when cast underwater (PC3).
New Monsters: Bhut (DMR2), Bird of Prey, Lesser Haunt (DMR2)
Changed Lesser Phoenix to Firebird (I12+MCSA2)
I'm not sure about the Druid change, but the rest is excellent. He's looking for any input help, so check it out if you have any interest in that sort of D&D.