I think I'm one of the few non-DT players who knows DT pretty damn well as opponents. Sorry Bedzike, but from the sounds of it, you don't. :/
Been observing them cloaked for a couple years. They run a tight ship with all decent, social players that elevate each other to a higher level. One on one, they're simply good. But put them in a group and their social skills show: their teamwork trumps that of most other groups who are either too unorganised, too inexperienced, too cocky or naieve or simply too ego-centric to beat them.
To take 'm out you have to know their organisational weak and blindspots and weaken as many of them at the same time as possible so your teammates can finish them off before they get a chance to cover for or restore one another or themselves.
But above all... Be as unpredictable as you can be and don't for the love of all that's sacred to you let them know your tricks!
Think it's save to say I'm one of the few peops they've learned to change their organisational tactics for once they know I'm around. >.>
As for the rest, you're working off assumptions a lot. :/ Assumptions are the mother of all mess-ups.