You can be very good at feinting and not be very charismatic, the same with intimidate. Charisma just helps, especially at low levels when you aren't that skilled yet, and natural talent shines through more than experience.
Characters with low charisma just aren't as socially adept as those with high charisma, and being able to read your opponent in battle is an aspect of that (like how Iajustu Focus was Charisma-based, I believe. I might be wrong). You need to read people to intimidate them properly as well, true threats require finesse. Unless you have the feat that lets you substitute your Strength bonus for your Charisma bonus, at which point you've learned how to gets the same results by merely cracking your knuckles and looming ominously.
Back on topic, you'll find that Pathfinder didn't fix the disparity between mages and fighters, but it closed the gap quite a bit, mostly by giving goodies to all the warrior-types and nerfing most of the broken spells (like Polymorph), and taking away the more broken class features (Wild Shape is much, much weaker now but still good enough to want to play a Druid). Many still think that Rogues are underpowered, but honestly you could make the ability to find and disarm magical traps a feat that also grants a bonus to those checks and you could cut the class out altogether. Heck, give bards the ability to disarm magical traps and they suddenly become a much better class.
Bards are actually good now, especially with Ultimate Magic, which gives them some awesome options. I'm partial to the ones that reduce your spells known in exchange for cool effects with your bardic music, then combining that with extra rounds per day for a pretty nice suite of options.
Pathfinder also does something that 3.5 did not do well: introducing new base classes in supplements that aren't terrible or otherwise identical, yet crappier than an existing class. They're all quite unique, with the possible exception of the Samurai and Ninja which are the Cavalier and Rogue with eastern flavor and a couple different class features.
As has been mentioned above, classes are now worth taking all the way to level 20, especially since the mage classes tend to have "paths" that give them good abilities at higher levels, while the warrior and thief classes tend to have "talents" that can be selected at every other level, which start out about as strong as a feat but which get stronger as you get to higher levels in that class.
Most prestige classes got another goodie or two as well, while others stayed about the same. The Mystic Theurge got a few new tricks up their collective sleeves, while the Assassin lost its casting (which was always kind of strange anyway) in lieu of some extraordinary class features.
All base classes and prestige classes have a "capstone" ability at 20th and 10th level, respectively, making dipping less attractive.
That's about all the big changes. Most everything else is either pretty minor or fairly specific.
In general, I find Pathfinder to be more fun. It feels like more though and testing went into the rules before they were released. If only WotC had done more of that, maybe Truenamers would have been playable. Ah, well.
