It is pretty rare that I want the bike to be going slower rather than faster. Even if you’re descending on dirt on an uneven surface in the wet with a heavy load it’s normally traction that’s the problem rather than running out of brakes - even rim brakes. Of course discs are nice and more reassuring etc, but they can also be a hassle when you’re packing your bike for a plane, and if you need a new wheel on a tour etc. I really don’t know if I’d go rim or disc if I had to replace the bike. These days all the best frames seem to be disc, so probably disc when it came to it. Pads for rim brakes are important of course. KoolStops are mandatory.
Again with the whole 26in vs 700c thing. Hmm. I do think that 700c roll nicer on rough roads; it’s noticeable. On the other hand when I cracked a rim in France I got a second hand 26in wheel from the local bike rental place in a small town on a Sunday morning fitted in half an hour for 60 Euro total. That would not have happened with anything 700c or disc. Through axle? - “Qu’est ce c’est, monsieur?”
Marathon Mondials do have a nice pattern. They feel slow on tarmac, but they are good all round and I like them on dirt. It’s a pattern that will get you most places. For extra traction you can run them at even lower than their ideal off-road pressures without pinchflatting them in my opinion. Pump them up hard and they are good but not great on bitumen. I don’t think they are puncture resistant though, and I can’t yet comment on how long mine have lasted, but they are holding up well. I recently met a guy whose first set had done 25,000 km and whose second set was on 15K so I’m hopeful. As for the tube/tubleless debate I’m not qualified and (for now) I’ll leave tubeless to people who are confident with it.