Shadowed Soul is good only against necromancer. Against other classes it's completly bad (ok, it will increase your hex damage, so if you really like this bad spell, go for it). It is bad because you lose too much survivability/group support to get that.
DT is not supposed to use CoA only, CoI is also very good for PvP. The short cooldown means you can switch frequently and it really is very good against mages/dts/pom/tos, not only because of the mana drain, but the retributive damage is sick. Feated CoI = I win button against the classes I mentioned.
I need to test if it works against ranger/conq dots and if it's viable or not, but I doubt that i'm going to waste my time on a class getting a revamp.
I personally hate talisman and i'm not going to use it unless they revamp the DT and it becomes a must have weapon, but if I change my mind, i'd run with something like this:
http://goo.gl/KPTXGl
Feated SoC is also very good, the damage is very nice and will help your survivability as well.
TBH with you, I don't see how tali can give anything good for you unless you're interested in duels.