You're right and I stand corrected re Eldritch strike. Only knew about blast and had to check DDI. I agree with a 1h weapon you can use curse and finesse to get 1d8 (rapier) +cha +1d6 +1d8 with nowhere near the restrictions of a rogue's 1d4 (dagger) + cha +2d6 sly flourish sneak attack (excluding feats).
That said it is potent but not crazy overpowered and is one of the few hybrids where you can use both powers on an at will. I think a good ranger build would definitely keep up.
Thx for schooling me on warlock-assassin hybrids