A massive point you got there. Here's the thing, there's always (mostly maybe) an advantage and disadvantage to almost everything in the world so it's pointless to not do something because of some disadvatage(s). What we need to do is to weigh then judge accordingly. The merit system is great which will provide much more deeper meaning of the ranks in Bitcointalk. Aside from trust which are more like about DT members, we can see the general point of view regarding that user in merit system.