Challenge mode old school raids?
In the most recent Dev interview, Tom Chilton said that the new feature will allow players to see and complete old content (implied that some content had been skipped by players or was otherwise inaccessible). Based on this, I personally think that the feature is going to be Faction Defection, where players can at some point in their journey decide to convert to the opposite faction. This works because:
A. Pandaria has been leading to this lorewise, at the very least at the Horde->Alliance conversion level, as shown by Lor'themar and the blood elves and by Vol'jin, all upset with the direction the Horde is headed in
B. This would absolutely, in my opinion, be the most efficient and smoothest way to open up old content to players who were previously only able to see their faction's quests and storylines (usually because many people are unwilling to level a whole new character on an opposite faction where they have no gold, among other obstacles)
Of course, there are issues, such as losing racial identity, or causing faction imbalance as players surge towards the side that is more populated. This would also cause Blizzard to lose some money in faction transfers. However, overall, I believe that this would be a good change, especially because no one is forced to do it. There will always be people that would oppose such a feature because they are incredibly dedicated to traditional lore, but if the plot of Pandaria continues in the same direction, I think that this feature would make perfect sense in context.
What are your opinions on this?
I think you've taken's Tom's comment and gone completely the wrong way with it. Point A, regarding the Lore, has been more about showing the Horde breaking apart whilst also showing the Alliance isn't an option. It's all setting up the final raid, and for all we know the Horde that comes out of MOP could be stronger and more united than ever before.
Further, the option of joining the Alliance has been specifically closed down for the Blood Elves (part of me thinks such an explicit move was a reaction to all of those 'we'll trade you Blood Elves for X" posts).
As for point B, that it would be the smoothest and most efficient way, I have to question the use of those particular words when all the downsides you point out and the sheer mechanics of implementing it when set against what is really the smoothest and most efficient way, using their new level and gear scaling systems coupled with a structure that rewards doing old content (i.e what 5.4 is likely to bring).
So faction defection? No. Level and Gear Scaling system, yes.
dota style bg's or some kind of dinamic events leading to the final battle of expansion
Yeah, I guess your idea does make more sense haha
Although I would love some way to explore other faction content without having to roll a new toon or pay for a faction transfer.
---------- Post added 2013-03-11 at 02:03 PM ----------
I also just realized, though, that lower on the front page in a Tom Chilton interview with Twizzcast, Chiltok mentions gear scaling as something Blizzard would want to do in the future. This fairly blatant mentioning of this idea makes me believe that the new, more "secretive" idea will be something else. Although, again, as you pointed out faction defection is a fairly unreasonable idea no matter how fun it would potentially be.