What options are available in the book for someone who doesn't want a 'class on rails?'
I'm the type of guy who regularly multiclasses (even PMCing sometimes,) and likes a bit of freedom in my character design. Speaking of multiclassing, how does it work with some of the new classes?
(To clarify, I'm only vaguely familiar with Essentials, so the 'on rails' comment is mostly based upon reviews given by others and what little I've seen in play.)
The vampire and executioner are very much "on rails". They are designed in such a way where the former, as the only version of the class, has no other options outside the book to swap in and the latter, having no at-wills, encounters or dailies with an actual level number, can't take anything but utility powers, feats and paragon paths from the other Assassin. The vampire can multiclass, he does have powers that are swappable (he does get a numberless encounter power, but he also gets one at 3, which is replaced at 17, which can be power swapped for a multiclass power). The executioner is pretty much screwed for multiclassing, he has nothing that would work for power swapping (except utilities).
As far as multiclassing into a class goes, there are no new multiclass feats in the book. The only way "in" to the vampire at the moment is the half-elf feat which let's you count as m/c'ing with the class you got your dilletante power from (as well as making the attack charisma based). This can be nice with the vamp since you can grab the attack that gives Cha mod thp, and then later grab the charisma based dominate dailies.
The blackguard, has his encounter power set in stone, but his dailies and utility powers are all level numbered, so he can freely grab from normal paladin builds if he wanted to. Similarly, paladins get more options to use from the blackguard pool, including at-wills they can take. They can multiclass swap anything, except for encounter powers.
The binder is like the warpriest. It is given a suite of encounter powers based on their pact (as well as their at-will), but their dailies and utilities can choose from anywhere. All the options are available to the original warlock classes (although the at-wills are a bit hard to get with all the warlocks having their at-wills on rails outside of hybrid or human, etc). They can multiclass fully as all the powers have a level.
The death domain warpriest, the gloom pact hexblade and the necro/nethermancer mage are all more of the same from the previous essential book (although the Death domain warpriest is implement based instead of weapon based). Of the Ebook classes, mage and warpriest are the least on rails of any of them.
Basically a mage is pretty much the same as a wizard, but has prefered keywords for spells instead of an implement that may prefer something like save/ends effects. The warpriest has some of his powers picked for him by his domain. The fighter, on the other hand, has no daily powers and is given a single encounter power multiple times, so his only choices are utilities and at-will stances. So the 'on-rails' is refering to classes that assign you powers insead of letting you pick them (like the original warlock did with your at-wills).
As far as multiclassing with essential stuff in general, there is really only the old multiclass feats so far. Some classes can't paragon multiclass (well, they can, but you'll be getting less use out of some of the feats because they won't, for example, have an encounter power or daily power to swap out) but there is supposed to be an feats article this month to address some of that.
when you have none left.
