There is pretty much no way to introduce ranged weapons that meets two basic criteria: a semblance of logic (e.g. not having call lightning like lag) and doesn't destroy game balance.

Take the mob tracking issue, you'd have to go in and code every mob that doesn't track, guildguards, cabal guards, cabal inners, just to mention the easy ones, to be non-targetable, otherwise a ranger with enough patience could just plink away at them until they are dead.

I agree that rangers could use some spicing up, but giving them ranged attacks isn't the way to go, if you want the project to be done this decade.