Yeah on my current account I have the BOA Dreadmist Mantle, BOA Headmaster's charge, BOA Inherited insignia of the alliance, and BOA Discerning Eye of the Beast, that I pretty much send back and forth between my twinks as needed. I currently use em on all on toons who can, specifically my 16 Druid (gonna be a 19 FC), 10 Shammy (not sure if she's gonna be 19 or 29 yet), and my 29 Priest.
I was wondering about shoulders because I didn't know if I could use the Mail ones on my druid (for better armor) or if I had to go with the leather ones. As it turns out, I figured out I can look up the items using Atlas Loot on those specific characters and see what they provide at the level I am at. The mail ones (herods for example) are certainly Leather if its on a leather wearer at the time with the same armor value as any of the equivalent leather shoulders. Likewise I imagine the plate (valor, stockade, etc.) are mail to a warrior/paladin pre level 40.
Since already have "caster" shoulders (which pretty much cover me for any lock, mage, priest, druid, resto/elem shaman, holy paladin), my next pair will be a melee/hunter one, so probably the shadow craft or the WG PVP ones with resilience. The PVP ones are better Stamina which I prefer for my druid, but I am still a ton of Shards away (like 143). So I may just get the Shadowcraft in the meantime (since I have 40 Emblems and 0 Patience lol), OR get the hunter ones so I can use them on any hunter/shaman/paladin/warrior I want to go melee with, and just wait for the PVP leather ones to use on anything but my casters, which wouldn't want em anyway.