I have to agree with empireaddict on this one, while dwarfs have fewer infantry choices, they do have 3 flavours of war machine which compensates somewhat in my view, I'm happy with the infantry choices you have as they fill specific roles within the list quite nicely, warriors are a solid foundation, thunderers are shooty and defensive, rangers are good all round and trollslayers are your 'flavour' unit, you can even add some speedy 'alpha strike' capability using gyrocopters
having said this, if I were statting ironbreakers up, I'd consider giving them an extra attack and perhaps a 3+ armour save
Hammerers would get an extra attack, immunity to terror when joined by the general is a nice touch
I'd also make both units a -/1 choice AND make them elite to restrict their numbers further, they're very much a fluff choice rather than anything the list is crying out for IMHO