Sure
The main problem of IH and Erebor is their slow movement speed. It has been the same in 4.4.1 as well, but back then you could use the ravens everywhere, so you could win every fight (more or less), since the debuff from the ravens was really stong.
Right now their normal sword units are not bad, but they aren't really better than for example Gondor Sword. But they are much slower.
Because of that (slow, but only average standart units) both factions (IH and Erebor) strggle to mantain mapcontrol in the eg-mg. And even in head on fights you can beat them quite well, depending on you faction.
And since they can't hold controll of the map early on they have less money available (mapcontrol isn't as important as it was in 4.4.1, but it's still important).
On top of that their slow speed makes them vulnerable to ranged Units, since you can kite them quite well. And when you combine some ranged units with cav it is even worse, since your pikes will get shot down and once they are dead, well, then you will loose everything, most likely^^
And because of your speed you can't retreat from a "bad fight", unless you stay near your mines all the time.
Of couse IH and Erebor are stong in the later game, with a stong army of heroes and upgraded elite units, but getting there isn't easy against a good player.
I hope this was the kind of answer you were looking for, if you have any further questions feel free to ask
best regardes,
Seleukos I.
ps.
http://edainranked.com/Statistics%20_Factions.html This is a Website designed by MaxPower and there are some nice statistic about Edain, based on 1v1. There isn't that much data yet (especially since IH and Erebor aren't played really often), but you can get a first Impression.
Edit: Looks like only true WK was quicker