The 3.5 PHB, which clocks in at a hearty 317 pages, has 11 classes, 7 races, roughly 100 feats and 300 spells.
Yes, and IMHO they were too many

And I mean too many classes and races, but OTOH not enough feats at least. It wasn't bad, but it could be better.
Here's some examples why I got that feeling back then already after just a few months of playing 3.0:
- IIRC if you play a specialist wizard, 1 of your 2 new spells known when you level up must belong to your school, but there are not enough spells in the PHB to cover this requirement for almost all school, unless you purposefully select to learn spells of lower level
- there are no feats oriented at making class features more versatile, such as expaning the barbarian's rage, the the rogue's sneak attack, the ranger's favored enemies, the druid's wildshape...
- there is just one fighter-only feat, which means just one single (optional) little feature for an entire class to mark its uniqueness
- there are very few Rogue's special high level abilities, and very few Bard's songs
I would like a PHB that gives immediately more depth to the classes by offering basic alternatives to their class-specific features. Had they included 2-3 classes less in the 3ed PHB, they could have certainly made space for all those examples I mentioned above.
Then additional classes should deserve a throughly treatment like in 3ed Complete Books, where new classes were introduced and they had (presumably, I don't own those books) enough material to stand on their own.
Too many classes in the PHB means they will have low depth/customization, meaning supplements will be more necessary.