>>45525815They're not bad at all. Their biggest drawback is having lots of weaknesses on top of slow speed. There isn't really a whole lot to be done about this with the existing mons, but there are some things that can be done with small changes.
>AccuracyThe accuracy/power of Rock's best offensive moves is lacking. When you're attempting to sweep, you need more power and/or more reliability than Rock offers. Having a way to boost accuracy or introducing new Rock moves might rectify this.
>AbilitiesSolid Rock is the best ability these mons have, followed by Sturdy. Rock Head and Reckless are completely useless, with no moves to take advantage of. Sand Veil is okay but pretty unreliable with such potent weaknesses. Giving them moves that complement these abilities or replacing them would help a lot.