I feel like the game is a bit too easy, and the miners are overpowered. I am currently at the 100th moutain, most of my DPM comes from miners, and I haven't felt the need to ever prestige.
I think all incrementals are pretty easy, until you try going for optimal builds or speedruns/achievements. But yeah atm you don't need to prestige to beat lvl 50. I never really liked prestige/dps-check walls, but looks like many people expect them. The plan is something like for lvl 50 to be the first "ending", and then have a dps check boss at lvl 75, then lvl 100 will be the real ending, that might also require obtained special artifacts from spelunkers/forging/alchemy, which will require prestiging. But then lvl 150 or 200 will be another secret ending, with some secret bosses sprinkled in as well. You'd still be able to do a lot of the early content without prestiging, but it would be harder/slower.
And yeah Miners are top dps because they have so many on-hit procs alongside pickarang that just goes off, while some others are still unfinished. But currently in the very late game ballistas are top dogs, followed by laser cannons (due to rune of machine). Plus of course different dwarves offer different utilities. Demodwarves are just weak atm though lol.