Well it has to be better, or you'd use a longbow instead, wouldn't you?

Why not use a feat to buy longbow proficiency?
I'd think a lot of folk have already ruled that not allowing rogue abilities to be used with other weapons is wrong?
I know the worry is ridiculous abuses (3.5 spike chain trip rogue, jeesh

), but in 4th ed I don't see the problem.
All other superior weapons are +3 hit.
They offer distinct advantages: higher damage, often have High Crit, or off hand, or high damage
and Light Weapon etc.
This weapon also has a slight disadvantage with the range (which is fair and makes sense).
so, +3,
miniumum of +1 dice increase and something else to keep in line with other Superior weapons, seems reasonable to me
Otherwise, treat it as a Simple weapon +2 hit, +1 dice increase, reduced range as shown.
?