Which Dilettante power for a battlemind?

[Duff]

Another consideration on use of Eldritch strike for Heroic Battleminds is your GM's roleplaying.
If an enemy triggers an opportunity attack and ends up lying down due to flail expertise, they may be inclined to make sure they don't give any more opportunities. That requires a GM to think more about character knowledge than some will do

Also, Eldritch Strike and Twisted Eye combined will give basic attacks which hit harder and I think it's fair to say it's an unusual campaign/DM where you will run out of PP and have to use a poor strength based attack. The daily "Steel Unity Strike" can also cover some of this for you
Also, the 1/2 con damage and no riders or conditions of your Melee trained MBA is hardly terrifying and has the "opportunity cost" of using your interrupt for the round.