So patch 4.1 was yesterday, and I went through and did the questline in Stranglethorn. I thought it was pretty well done besides the lack of zombies in the zombie part of the line. I thought introducing you to each boss in Zul'Gurub was a great way of making it apparent of the war you are facing. The battle in Grom was my favourite of the quests and makes me wonder if the Alliance get the screwed in this regard. One of you Alliance types would have to tell me.
It is kind of disappointing that there isn't the same for Zul'Aman and I am only assuming this is because it is located in Ghostlands and a Burning Crusade zone isn't one that Blizzard wants to showcase and the current time.
The instances themselves weren't too difficult, but for people who have been raiding this tier I would hope they aren't too difficult for you since you obviously outgear them by a good margin. For the people they are geared towards I would think they are a bit of a challenge. For these people who outgear it, they can use the increased points, call to arms system, and of course achievements and rewards in these instances.
Overall I am happy with the lore and story of this patch thus far, and if you haven't seen the trailer for it well here it is
Enjoy the patch and its features. Of course make sure you take the time to experience it and not just rush through it as it is a one time thing and you won't get the opportunity again.