D&D 4E 4E Dual classing

there are three issues I can see with this.

1) There is no class level in 4e so there is no way to model what you're describing. A character has a single level.

2) Even assuming there were a way to model it, there isn't much way to balance out a character who has advances 2 levels as warlock (gaining all the warlock features and 2 at wills), 3 levels as wizard (same), 4 levels as paladin, etc.

3) 1e / 2e dual classing made no sense and lacked internal consistency

So, honestly, I don't think it could be done or would be desireable. In some ways, the paragon multiclass gets close to this. If you figure that you'd gain some features during those levels, and if you took all the swap feats you'd have:

2 at will from original (possibly 1 from second...don't have books handy right now)
2 encounter from original + 2 encounter from new (feat + paragon)
2 daily from orginal + 2 daily from new
4 utility from original + 2 utility from new + 1 from destiny

This is pretty darn close to a perfect split, IMHO

DC

I never liked the 1e or 2e dual class (as opposed to multiclass) options. It seemed too contrived to make you "start over" in the second class and to punish you with XP forfeiture if you "slipped" into the previous role (in a desparate situation, or whatever other reason). These were imperfect means to accomplish a desired end in those systems. No reason to imitate lousy rules in a new system.

The new multiclass feat and retraining rules are an elegant nod to the multiclassing problem, but do not address it completely.

See also the neighboring thread, http://www.enworld.org/forum/showthread.php?t=233116 "Dualclassing 4e Style."