I actually like diesels engines but I believe there is a place for them, and a place where they do not belong. If I owned a fleet of groomers and my own ski resort then I'd probably want diesels. Then again under those conditions I could control the fleet and the terrain where the fleet operates. Perhaps an oil company, with a fleet and my own recovery vehicles, then I'd also opt for diesel.
But for the private snowcat owner, operating a back country unit that would operate in places where a breakdown would be a big problem, the last engine I'd probably want is a diesel. We have to realize that these vehicles, whether on farmland or mountains, operate under conditions that are freezing, on rough ground, far away from a rescue vehicle. Even mixing in plenty of anti-gel, my truck fleet has had fuel lines freeze on the interstate highways, so I'm not sure I'd want to deal with that problem when a snowcat is stuck on a moutain or in a forest. And as diesels operate best when the engine is hot, if the snowcat is stuck overnight in subzero temps, getting the engine warm enough to start, and keeping the fuel lines from freezing would be a challenge. At my warehouse we use propane "torpedo" heaters to thaw our trucks, but then we have access to electricity, propane tanks, and a heater.
Diesels are great engines, but I'm not sure its the best choice for every application. Other folks who operate these machines in far more remote conditions than I do might want to chime in.