As far as multi-classing goes, Pathfinder has basically gone more and more in a direction of punishing multiclassing (by making it obselete). It has done this by adding quite a number of archetypes to standard classes, so instead of multiclassing to diversifying your character and/or picking up some skills typically part of another class, you can use one or more archetypes to swap class abilities in and out. There's less reason to multiclass than in some versions of D&D. (D&D 1st edition of course, multiclassing made sense and was kind of like, "Oh you're so awesomesauce!")
It also recently released the Advanced Class Guide, which created ten more classes that are "merges" of your basic classes (e.g., the Skald, which is basically a bard + barbarian merge).
You can still do some multiclassing, but if you don't want to shoot yourself in the foot, you have to make sure your classes synergize appropriately.
For example, I'm currently working on a character who I thought would be an Oracle, and I saw there was some decent basic synergy with Paladin, but the multiclass actually is more beneficial as Paladin with a dip into Oracle versus Oracle dipping into Paladin. (The synergy is that both classes have variants that will let you use Charisma as your base stat, even applying it to AC, some saves, and knowledge checks... all of huge benefit to a pally, and I even get four additional first-level spells.) Staying in Pally means I don't really lose much BAB (maybe just +1) -- necessary to be an effective pally -- but you can make up for that in many ways when you're a BAB = Level class.
Unfortunately, for spellcasters, the rule is "Thou shalt not lose caster levels." I do have a rogue who took a dip into Sorcerer, and since she had a decent CHA (14), she basically got a few first level spells that make her a better rogue, access to anything on the sorc list without needing to roll UMD, etc... all things that increase her basic utility. But a Sorc dipping into rogue? Not nearly as useful, and because CL is tied to spell potency, spell quantity, and spell levels available, you've shot yourself in the foot compared to a straight sorc. Your potency as a spellcaster is notably diminished.
So Pathfinder classes are less restrictive than traditional D&D classes (and you also get traits, to give your character a few extra bonuses for diversity flavor) since you have a ton of archetypes as well as racial bonuses you're allowed to swap. But in the process they're taken away incentives for "real" multiclassers.
Character creation is actually really easy whether you're playing straight or multi-classing, if you've picked up Hero Labs or some other electronic software on which to create your character (it handles all the number crunching and interweaving for you -- you can even flip on spell effects, make alterations to any form of bonus, etc. as you play). But the base for HL is $30, and you have to purchase each rule book extension to have that module added to your character software (typically $10). Still, if you can afford it, it's a godsend. I love it. I sometimes just sit around and make up characters I haven't played before (class and race) just for fun and to understand the mechanics/synergies better.
I hate what little I've seen of D&D 4e. Sorry. It was basically an attempt to port MMO game styling into the D&D setting, to pick up the WoW and young player market. (Kind of like Dragon Age 2's attempt to appease console players, that ended up alienating old-time players, so now they've merged concepts more on DA3.)
We are considering running some pure "oldie dungeon hack runs" in D&D5e, so I ordered a PH this week so I can review the system and let everyone know how it works. I know Tomb of Horrors too well to play that, but it could be fun just to throw aside a real campaign and try to blitz through something like the Slavers modules, which I barely remember any of.
Getting back to WoD briefly: Mostly you are confined by race -- all races [vampires, werecritters, fey, mages, prometheans, etc] use "similar" setups (you can see the conversion of abilities if you just look at the templates) but each is flavored a bit differently. And then you basically get a blend of focuses (usually "five types" of critters in each "race" of monster), and these types are broken further into types of sects, that emphasize some abilities over others. You are not restricted in what you can learn as you adventure, but you usually have to handle it within the roleplaying context -- for example, when I wanted to learn a vampire ability that my sect did not specialize in, it cost me a bit a more and I had to find an NPC within game who was willing to barter with me, I taught them something I knew or performed them a service, in exchange for the knowledge. Anything that is a normal type skill of course can be learned within game, by doing it -- you can then burn your points to acquire points in the skill. The number of levels you have in a skill or ability determines how many bonus dice you get to roll when you use that ability (or, for "class/race" skills, what abilities you might actually have since things are tiered.)
So my vampire Lindsey was part of a modern sect (tech savvy) and a very young vampire, she had just been turned at age 17; she was fast (celerity) and also had high CHA/influence skills, she could shoot a pistol really well (her dad was a cop), and during the course of the game I expanded her powers a bit to be even more charismatic, she could foretell a bit of the future, and she learned how to ride a motorcycle and do some parkour stuff (while running celerity... haha, yes, she just runs right up that wall). It was a hoot. But I didn't really feel limited at all, my powers and abilities were always expanding rather than having to wait for 6-8 sessions to pass.