I wrote ages ago when Ulduar come out about how grateful I was to be in a guild that was ready and able to walk into new content on the day it came out, and also that I was part of the raiding team that would be stepping into that experience.
I am guilded now, not as a raider though, yes I am getting most of the runs I want be it – trade pugs – GDKP runs, or guild/pug halfsies – but as much fun as I am having keeping myself occupied with them, dailys, Pvp and more Pvp I am feeling a little lost – What is the point in chasing that offset piece, that gear with the haste for 3.3 – saving for the 19k odd Im am likely to have to spend on Anub’s much wanted trinket on a Gdkp when I am not raiding – when I will be lucky to see Icecrown in my current position. At this point, I won’t be stepping in, finally using all those stupid icecrown rune bonus’ from the Ebonhold dailys, and the bones I collected.
I would like to think I have taken pride in my gear – I was congratulated on one app before I left my old server to for having the best enchants and gems. Congratulated. Like I would do anything less. I have taken care. I do care about my gear.
If I can use gearscore as a rough comparison to the other people I see running around, the top tiered raiders are 5200-5300 Gearscore, and I am sitting at just over 5100 – I’ve done pugs where they spam the GS and I’m normally at the top, or near the top. Most of the rest of the non top raiders are around 4900 so I’m not in a bad position, but all this means squat if I am not going to use it – and depends on how many people take their Shadow Priests out of the closet and if we are going to scale better as to how much demand there will be for more than one of us in a guild.
Sure I could top TOC 10 man for the rest of my days.
So hear that longing in my words. I miss organised raiding. What am I going to do about that? – Not sure yet – but the seed has been planted – and I will be watching it grow.
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Pugnacious Priest's Warcraft Blog 
The question is… do you want to become a raider in your current guild? Because if no, you’re going to have to start shopping for another guild… again.
Perhaps it would be worth discussing with your current guild leader that you were thinking about apping and testing the waters a little. It may be that he’s willing to take on another shadow priest as your current guild only has one.
Also I looked into the bones buff and it looks like they won’t be usable in ICC – which isn’t hugely surprising tbh. A 5% buff to all dps, a 5% damage reduction to all tanks – seems unintended given all the work that Blizzard have done to cut down on consumables for raiding (Battle/Guardian Elixir changes, specifically)
As the guild leader of a raiding guild, I can tell you that the key to forming a successful relationship within your guild is honest communication between the leadership and the membership. This is a road that goes two ways. While it is important for the leadership to be frank about what they plan to do with the guild, it is also important for the membership to bring their concerns to the leadership.
If you’re feeling the raiding bug coming up again, you should ask your guild leadership about their plans for the future of the guild, and how much and what kind of raiding those plans entail. Also important to ask is where they see you fitting into those plans. Once you’ve obtained that information, then you can compare where they want the guild to be, and you to be within the guild, to where you want yourself to be.
If you’re satisfied with what you’ve got, then you can feel secure in knowing what’s to come, and if not, you can take steps to make reality closer to what you envision your ideal to be. But I would still suggest keeping your guild leadership informed of your plans, so as to avoid stepping on any toes unnessicarily.
If you aren’t pleased with your guild’s direction, I’d say act on it. I no longer play retail because a couple of randoms (priests) outgeared me and replaced my position in progression. I’m not implying anything, your gear sounds impressive, but do you remember how quick dungeon to heroic to raid gearing has become? IC will bring very fast upgrades, despite the ‘gated’ system, and you might find yourself on the sidelines of the action. Unless you plan on meeting IC casually at your own pace. But that’l contradict your post a bit. Do what ‘you’ enjoy, and you’ll solve this dilemma. 🙂
If you want to raid, now would be the time to act. Right now you have the advantage of being freshly geared. Once IC is underway, assuming it isn’t puggable like ToC, you’ll end up falling behind. What’s more, since ToC is so accessible, there will be a sea of applicants in ToC gear to compete with. You stand your best chance getting into a good raiding guild now, while they don’t feel they’ll have to gear you up before you are ready for progression.