Yeah, i only use the hoe for building purposes to make flat land so it's just more convenient to build on. But you can definitely build bases without it, even on generally uneven terrain, just build supports. Some people seem to really depend on it though it seems, whether to make literally impenetrable walls, aka exploiting the AI, or just flatten out terrain in combat related scenarios.

But i must say, moats and raise ground walls are without a doubt the biggest cheese.

So yeah it definitely can be beat without it.