On face value it is odd. Elves have lived far longer and are way better at everything, etc. etc. etc.

But game balance wise, rohan has to have something special about them. No monsters, no super epic heroes, no warmachines, etc..
Rohan is very much a mongol horde analogue. They are horsemen. If anyone should be able to throw sticks or shoot bows from horseback it isnt a stretch to think of Rohan being that choice.
A super shooty scouting formation isnt that odd when taken into context with the rest of the book.

True.The Rohan faction desperately needs something with archery power.They have almost no archery talent in their list,aside from the fact that regular Rohan rider can shoot.

Thats the trouble of isolating one profile without considering the overall picture. How good would the outriders be shootong with just 2 dice needing 4+ and at the same time taking hits with just D4? Pretty rubbish, nobody would use them.

I see what you mean.Although I personally would not use them anyway,I'd buy normal RoR and us them for shooting.Not as effective,but cheaper.