0:25 - Could there be unique talent tiers for specific specs?
3:08 - Could the BattleTag system allow for an account-wide ignore feature?
7:29 - Why do I care about expertise as a Mage?
12:26 - Should Spirits of Harmony be BoA?
16:55 - Would 15-man raids work better than splitting 10 and 25man lockouts?
21:35 - How do I deal with having too many raiders on the same tier token?
25:51 - Do we love big numbers too much to ever appreciate an item squish?
30:43 - Should we be able to sell Lesser Charms on the AH?
35:02 - How will the split lockouts in Korea affect the world first race?
I think one of the reasons they don't have Spirit of Harmony as BoE is how it would affect professions on your alts.
Many professions can easily be maxed via the auction house or farming, without even levelling your character. For example if your level 85 alt has 600 Inscription, you could easily craft all the epic staves/off-hands if Spirits were BoE. Altoholics could craft just about anything for themselves in this manner.
You might say there is nothing wrong with that, and I would agree. If somebody wants to farm all their motes on 1 character then good for them.
But as it stands right now, the system encourages you to level up your characters. Otherwise you won't have access to craft the very best things that profession has to offer.
They keep making the BOP crafting mats non-binding because that's their plan, not because it turns out to be a bad idea every time. They came right out and said that spirits of harmony probably won't remain BOP for the whole expansion. I would speculate that they want crafting to focus on personally farmed mats for the early part of an expansion, and then on raid drops later.
I'm not sure if there's a really powerful argument against BOP crafting mats--I feel like Lore is searching for one and hasn't really found it yet. It mostly boils down to how big of a speed bump you want the game to have in the way of getting crafted epics while gearing up for raiding. The bigger the speed bump, the more rewarding it is to be a really dedicated crafter early in the expansion, but the more progression raiders are forced to spend game time paying attention to a crafting system they aren't necessarily interested in.
As for lesser charms: I think people who want something to do with their lesser charms are mostly being shortsighted. There will come a time when you will absolutely appreciate your stockpile of lesser charms, when nothing else is pushing you to do 45 dailies per week. Sure it's annoying that they take up bag space, but that's the only problem they need to solve (and will solve in 5.1, IIRC).
Spirits of Harmony being BoP is a way to throttle initial crafts and the effort put into them. Because there can only be a limited amount of them created per server, it provides an argument for all but the most hardcore raiders to not get this super expensive item immediately, while in the future, as the need for spirits goes down, this item can be used as catch-up mechanism by a new leveller (or alt) for a smaller amount of effort and/or gold.
Argument against BoP: It forces you (or another person in your guild) to farm Spirits on a character they might not ant to play in order to get gear on a character you DO want to play. e.g. If I wanted the epic crafts on my Shaman, who is Alchemist/Engineer, I'm forced to find myself a Leatherworker and either pay him for his/her time or level my Hunter up to 90 just so I could farm the motes/spirits required to craft the item in question.