Having a reset option is like... graduating from college with a degree in Water Reclamation Engineering, then deciding that just because you're bored, you're going to use a respec option to become a doctor within a couple of minutes.
For other games, I'd agree. However, for Skyrim, it's more like an individual graduating from college with a degree in Water Reclamation Engineering and wanting to have it changed to a degree in Medicine, but they are already demonstrable experts in the field without having the piece of paper to back it up. A warrior cannot just respec to become a mage in Skyrim without having skill points in the School of Magic. You aren't going to get far as a mage without those skill points because the perks have minimum skill levels that have to be met before you can even invest. I think if any game is responsible enough for a respec option, it is Skyrim because the leveling system works very differently from the standard EXP system in other RPGs.
Rather than directly putting points into skills after you level up, Skyrim uses those skill points to make you level up in the first place. Assuming we were talking about a character who mastered both the entire schools of Magic and Shadow, a respec doesn't make you less of a master of those skills in the way that it would with Kingdoms of Amalur, which I thought had the most liberal respec option I've seen in a RPG in a long time. The only thing it does is reset the perks that give the skills you have already achieved some level of expertise in a little extra "oomph". You'd have to be a master of all three schools of Magic, Might, and Shadow to even get a respec option as powerful as the version in many RPGs. These types of people are hardly roleplaying anyway (unless they roleplaying gods), so I don't really see the harm.
Regarding the topic at hand, I agree that the level cap should remain as it is. Without a respec option, I wouldn't even forsee them adding extra "traditional" skill trees because most characters that will be going into the expansion will not be new. The best way to take advantage of those new features in that instance would be to create a brand new character, which I don't think is a great way of trying to market the new features that are being added. If they added any skill trees at all, I'd expect them to be done in a Vampire Lord or Lycanthropy type way in which the perks do not require investing normal perks.