I somewhat agree. I am actually quite surprised though, to see more votes in the passively buildable Ram Riders than the summon. I thought a summon would have been the way to go and to keep it to a bare minimum (Due to Dwarves being infantry-centred) so that the core of the faction is not affected too much, but I'd love to see what a dev thinks.
I personally see no true harm in adding Ram Riders into such a limited function and I am a multiplayer-person, so balance is extremely important to me. Yes, Dwarves are currently the strongest faction, but will probably be tweaked/toned down a little (that's what my insticts tell me about ET anyway haha).
Furthermore, I see the lack of cavalry not only as a unique feature of the faction, but also as a unique weakness. When playing against dwarves, I never really need pikes. Archers are mostly the way to go against them, I feel. With the summon, you can temporarily cover that weakness, that lack of cavalry . Besides, you need to get Dain to level 9/10 for that ability in my proposal, so you'll barely see it. It is just something nice to strive for for the fans, while not being impossible to balance, from my point of view. It comes late, has a short duration and Iron Hills are light dwarven infantry, so mobility might apply better to that concept. I even compared them to Warg Riders, and gave some ways in how they could be diversified.
I hope, nonetheless, that they will share some of their thoughts.