Would I put alignment in 4e? No way.
Will it be in 4e? Yep.
Why? Because 4e will still have character classes, hit points, armour class, and the other quirky matters that make D&D, well, D&D.
Alignment, in my opinion, has never been handled well in D&D. It was put in because of Michael Moorcock, but neither the author nor Gary Gygax fully understood the implications of the Law-Neutral-Chaos axis, and people are too nervous about defining the Good-Neutral-Evil axis for fear of offending someone.
In the end, as I have stated before, alignment becomes both an Absolute and a Generalized Notion. What does Detect Evil actually detect in a human being, if human beings are not in and of themselves evil and many acts fall into the level of "well, this might be evil, but it serves a greater good"? At that point, who could be smote/smitten? Do such powers only work on this absolutely, 100% aligned with one of the moral/ethical compass points, or do they work on anyone who appears to be generally, if half-heartedly, predisposed to backing one side or another?
Even in fantasy books we find moral conundrums, ones not easily solved by "this is good, this is evil". Why, then, do so many spells, powers, magical items and the like work as lodestones of unerring accuracy in this regard? It makes very little sense, especially given the guidelines characters are given about alignment "choices".
Either alignment must become just a rigid, defined, and hemmed in as it is for the Powers That Be or it is best to simply drop it.
One may always be a Hero without having to wear a white hat in public.