I agree with Ardenn on the issue with charms on main tanks.
It is quite bad in fact, and it has become a problem in nearly every guild. It is one of those things where you are damned if you do, and you are damned if you don't.
Option 1: Don't assist your MT in obtaining a better charm, and your guild progresses slower.
Option 2: Assist your MT in obtaining a better charm, your guild progresses faster, but individuals are at risk of losing money invested.
I have first hand experience with this, losing over 100k that I donated from my pocket to a former guild. I was leader of the guild at the time, and it was common practice that charms purchased by the guild remained guild property. The rules changed before I was paid back, and the guild also disbanded before I was paid back.
Our entire guild received the benefit of me donating the money, there is no question about that. But was it fair that I be the one who got burned when I was only trying to help everyone? I don't think so at all.
This is most certainly a problem, and is part of the problem guild MT's arnt replaced as easily as any other class. I feel this should be address, and I have brought this up before. However, the staff is leaning more towards a hands-off approach. I respect this completely, as its generally best to let the population sort out problems on their own. But, I do think they could implement features that would aid the population, or rather turn loss/loss situations into situations that resemble more closely that of a win/win.
For example, they could implement a charm registry. A registry that allows guild funds to be allocated to individuals, but with the ability to revoke funds (possibly at a penalty). This would reduce the dependence on building up 1 botted MT, as the funds could be changed to another toon. Thus, an active player has a better chance at landing the MT position in a guild rather then the guild eternally botting a warrior.