Although I can't speak for all the points you noted in your post, I'll try to answer them as thoroughly as possible. Though you might want to take some of it with a dose of salt considering the time.

1) The IC guild chat is simply a way to enhance our RP. Since random RP is rarer on Horde side than on Alliance (we have no Stormwinds), I sometimes like to think of an IC guild chat as an alternative RP hub for random RP.
How people want to explain it is usually up to them, as we don't really tend to philosophise about *how* it works IC. It simply works, just like that. Though the usual explanation is talking through the Hearthstone or a spiritual campfire which every orc can join at any time through the oath he has taken.
If you don't find IC guild chats all too appealing, that's all acceptable for us too, however. Using the guild chat is totally optional and we have an OOC channel for random talk as well, which is optional too (so yes, you'll have to type /5 for example first, though you could try downloading an addon like Confab for that as well, which stickies the last used channel, if you're an OOC spammer

). So it's eventually up to you whether you want to use it or not.
2) As I said on the realm forums, most people are having a Summer break right now or are trying out different games (like AoC), so things have slowed down a bit compared to the normal days. Though that's the case in pretty much every guild right now I reckon. Despite that, we're still well active and got at least about two to three events a week. I myself came back from AoC about a week ago. So despite any hypes, we're definitely still up and running.
3) We're part of an IC raiding alliance called the Covenant (a link to their forums can be found elsewhere on the forums, though I think it's in the membership section). They used to regularly hold Kara, Gruul and even (rarely) some SSC runs. Though right now, I think it's pretty much the same case as point two right now. A lot of people aren't around, among which some of the people who used to organise the runs. Last I heard, the raid planner is still up and running though. So it shouldn't be a problem for anyone to try and get a raid up and running, given there's a proper amount of interest.
Though even despite that, I noticed there're some random LFG calls on the Covenant channel every now and then, and I know some of our members raid individually with other PvE guilds. I'm not all that into PvE myself though, so you'll have to ask them instead.
4) Our first rank (New Blood) is pretty much a trial rank that most orcs keep only for a week or two at most, until he's taken the oath. After that, it will be up to the orc himself to decide whether he'll try to gain in rank or not. Ranks such as Nag'Ogar (there were descriptions of them on the wiki but it appears to be down atm) are gained by participating in certain events and being active and friendly enough.
However, as for storyboasting, there should be enough oppertunity for that. Mhokdor tends to organise some random campfires every now and then which are open for anyone to join and share stories at.
5) Can't say anything about that. I know I'm having fun anyway. ;3
6) As I said before, we're involved in an IC alliance called the Covenant. Although this alliance was mostly about organising PvE raids for the RP guilds, it is regularly used for WPvP events or random RP as well. The alliance consists of several RP guilds both big and small, and they all have a certain connection to each other. So it usually ain't too hard to get an event or whatnot running inbetween them.
As for you cheeky question: We had some orcs in the past who left us because of PvE. This is totally acceptable and up to them to decide, though you'll have to realise that you of course won't be able to follow every single business going on in the guild, like awareness on certain events or random RP. Although you will be tolerated to attend open events if you've proven to be a proper friend of the guild, you might still miss out on a lot of stuff.
Though it did indeed happen before, the guild is no toy you can just pick up, play with for a bit and throw away, only to pick it up again later because you're bored of some other toy - if you get my meaning. This did happen in rare cases before with orcs constantly leaving and rejoining to feed their PvE lust, but it's generally not encouraged.
Anyway, hope I answered most of your curiosity like this. If you've any more questions, feel free to ask either here or ingame.