That's not the answer. It would just aggro lock on the guard til death.
They just need to up the inherent hate of the pole tree, or the dps of the jug tree, or some such. A few simple adjustments could do the trick.
In truth, guard is just fine. Conq is OP and DT is way OP, especially on anything subject to magic damage. It's silly that 2 tank classes can top parses.