Can someone explain pandaren lore to me?

[not-so-spoilers: brief reference to pandaren starting area general plot in brackets; otherwise just speculation based on currently available information]

Lore nerds, I need your help! I have some questions about pandaren. I read WoW Insider's guide to pandaren roleplay recently, which was very helpful, but I have some logistical questions about the Wandering Isle.

We know that all playable pandaren will be from the Wandering Isle. That means they are descendants of the original adventurous pandaren that chose to leave Pandaria to travel the world. Some of that adventurous spirit must still remain, but I wonder if after so long they don't also get some odd birds that like their simple island life and don't feel the need to adventure. Not to mention that exploration would necessitate actually leaving the Wandering Isle. Just standing on the edge and peeking at other islands flowing by doesn't seem very adventurous.

Chen Stormstout, a native of the Wandering Isle, left the island to explore Kalimdor (probably spending most of his time wall-jumping trying to get into hidden areas). How many other pandaren have left the island in order to explore? Do they return - can they return? Have they heard about the changes to Azeroth - things like the orcs invading, draenei crashing, Gilneans emerging, goblins joining the Horde? After all, they've been on the Wandering Isle for centuries. They must have experience the Cataclysm, but do they know who caused it, or his fate? If not ambassadors, have knowledgeable pandaren returned to the island to teach things like Common and Orcish? To teach about the other inhabitants of Azeroth? [[ [[The final events of the Wandering Isle suggest that pandaren can communicate well enough with the Horde and Alliance and aren't too troubled by the sight of a tauren or human, but why is that?]] ]] How much communication is there between Shen-zin Su and the rest of Azeroth? 

Then, upon finally reaching Pandaria (for the sake of story I would likely skip the out-of-timeline leveling between 12 and 85), how would the pandaren react to their ancestral home? For other adventurers, it would merely be a place of rumor, novel but not personal. For pandaren, this is the place they've heard about in legends. Their ancestors were raised here; many of their customs and beliefs come from this place, although time and separation might have changed them. Can you imagine how sayings and beliefs from Pandaria, things like the need to expel negative feelings to avoid creating real enemies, would warp into empty platitudes on the Sha-free island?

Currently, the pandaren of Pandaria react to island pandaren as if they were run of the mill adventurers: you look different, here is some ancient pandaren wisdom you don't know. I think this could be explained away if the pandaren of Pandaria think of island pandaren as immature and uncultured. And considering how long the two types of pandaren have been separated, it's likely that everything from accent to lexicon to fashion has diverged.

But the Pandaria natives are extremely laid-back by necessity - it's more likely that they would simply accept the island pandaren back into their homeland with little trouble. This is probably too nitpicky, but I'd love it if Pandaria NPCs could react to player pandaren differently than other races. Imagine if a draenei questgiver were like "Man you have no idea what it's like to live in a spaceship" and your draenei is like "Um excuse you I think I do." Mayhem!