Might I ask why? A melee character can use his weapon for every swing, even if he's using a multi-attack power and hitting different targets (a fighter's Rain of Blows, for example). Same for a bow or crossbow user that shoots at more than one target in one attack.
Why? Only to force every thrown weapon character to get Bracers of Infinite Blades?
Batarangs hit multiple foes, the prince in Kull could throw the Gladius and it would return to his had, etc.
Elric called to Stormbringer and it floats to his hand after chopping and dicing some enemies (all on its own). The more dependent characters seem garanteed of this magic.
And how about we not penalize people that use melee weapons? They're vulnerable to OA, being flanked, sucking AEs and being the main target of the baddies. Maybe all melee weapons should make you immune to all of that? Seems that since they don't all have to have this magical teleporting returning property they have quite a bit of room in the enchantment department to be better.
I think you hit the crux of it: too "3.x" in thinking. And let's face it, the only "magic returning weapons" the PCs will see will be their own (if you take our party as an example, only one characer has a magic throwing weapon...
).
