I prefer Specialty-based multiclassing (aka the 4e feat-based MC) or flat-out Hybrids (as in 1e/2e and 4e) to the level-by-level multiclassing. Between Arcane Dabbler, Healing Initiate and Martial Training, you can almost see a glimpse of feat-based MC already (but Martial Training needs to give you one MDD, if you don't have one).
I think it all comes about what do you want out of multiclass, specialty based multiclassing is enough for some, but not all of the purposses. I'm not agaisnt it, it is good to have, but it doesn't fully substitute, nor preclude other options (like classic simultaneous multiclassing and level based multiclassing) and I think it is very important to get all three, not a single one can cover all that people want or need out of multiclassing:
Multiclass as dabbling.- In other words get a single new trick that is uncommon for your class, something special. Feat based is king in this one, and level based does wonders for those who aren't picky, yet single level dipping has become infamous and is very maligned and frowned upon. Simultaneous MC gives way more than that.
Multiclass as broaddening of abilities.- Understood as "more than just a small trick", all three can work propperly at this rate, yet level based runs the risk of not scaling propperly
Multiclass as blending of classes.- Simultaneous MCing is the best one here, that is what it doeas at it's core, feat-based requires a big expenditure of resources and level based is very criticed as "needing patching" and gimping the character
Multiclass as character evolution.- "I got tired of studying books and rather learn to fight with a sword than keep going the same" Simultaneous MCing doesn't fit the bill, by it's very static and set nature, feat-based also falls short, it takes a lot of resources and in the end it the character is still firmly grounded on the class of origin, level-based on the other hand works best for this purpose. (I liked dual-classing a lot for this purpose, if it just hadn't such draconian requeriments)
In the end it remains to be seen if I like the end result of their new MC rules, I hope it isn't as cumbersome and eventually allow you to be a full member of your new class (otherwise it would be a giant failure).But we will need something along the hybrids lines too, not a single multiclass method will be enough to cover all people want out of it.