Full Strip won't be a thing (at least not in the way we all remember it) for one simple reason: The inventory system. What happens when a victim's inventory is full when they get stripped? Do they drop the items that are stripped? Do they stay equipped? Having a skill that is either potentially grieftastic or fully countered by a game mechanic that has little to do with the actual battle system is just poor design.
On the other hand I can see strip skills applying a debuff that blocks the attributes from items equipped in a certain slot. Seeing that colo already sort of does this with equipment stat normalization we know its at least possible within the game engine already.
They could make it give a chance to make all equipment act as broken for 10 seconds. It would still be equipped. They could also make it additionally increase damage by 25% for 10 seconds on monsters (including bosses), since they don't wear armor.
But, they removed many Thief skills already (Stone Throw, Back Slide, Steal), and nerfed the way Cloaking and Hiding worked so that they couldn't be used in battle (for Assassins, anyway).
Beastmasters didn't exist in RO1, so I'd say we have to get out of the mindset that certain classes in RO2 are directly related to their RO1 counterparts, and will advance as such.
Even if they borrowed names from RO1, we can't expect it to carry the same meaning. Look at Cross Impact..
All I hope for is more build variety!
Sorcerer and Ranger are most likely just descriptions more than pulling names from Third class. The names could also just be mistranslations (which do happen a lot in this game), but I'm unsure. Their clothing looks nothing like Sages or Professors, and also looks nothing like Sorcerer clothing, but it looks closest to Sorcerer clothing. However, saying it looks close isn't enough of an argument to say that they're based on that class.
Honestly, the classes in this game seem to pull abilities from many classes from RO1, not just their own branch (look at Soulmakers, for example).
Still, all of that considered, I could still see RO2 using RO1 as a template. Why? Because that's how they started out, even though they changed 95% of it. GOTW was already changed 95%, so one could say RO2: LOTS had another 75-85% of content changes since GOTW. Basically, RO2 is maybe 1-10% of RO1 at this point, but that might just be enough to hope for classes to be referenced, at least in name, if not appearance.