I feel that dwarves are substantially weaker than the other races, but also don't think there is much to be done about it. From a design standpoint, it makes sense that the three starter races mimic the three basic powerups.
I do wish that more shop items supported them. The Fireheart is good, and that's about it. I mean, sure, the Cauldron is good for dwarves, but it's even better for halflings. Like Darvin said, resistances are good on dwarves, but can be leveraged even harder by humans and orcs.
That's what it always comes down to. The question isn't "Are dwarves better than going Hoarder?" but rather it's "Do dwarves give an advantage that justifies the opportunity cost of taking some other race?"
In the end, DTD is a non-competitive single-player game, so it doesn't matter if all options are equal, just so long as they are functional. And dwarves are functional, just less so than everything else.