Since I've already vented my spleen on this a couple of times in earlier topics, I won't repeat the details here. As far as I'm concerned, multiple attacks against the same target should die in a fire, for all characters, all the time, absolutely no exceptions. It always breaks somewhere.
How you then handle single attacks against multiple opponents can be done in a variety of ways.
Admittedly, Twin Strike looked nice and balanced on paper...then as play went on the effect of that simple little power became apparent. Doesnt matter what you do, more attacks proportionally blows balance out of the water
Lets face it, the pre-errata 'Twin Striking Half Elf Diletante Avenger Daggermaster' should have taught us something