Ok. First the inruns,  they are never quite as straight forward as "the park" in fact the inrun can be downright dicey at times making getting to the jump switch damn near harder than actually putting anything to your feet. Of course if your coming in forward it's just a little more entertaining.
Second, massive step downs, dropping 40+ft (in relation to take off) As well as normal distance and height gives you that much more speed upon impact and makes every trick more difficult. Imagine a park jump of similar proportions to Sammy's first hit. This is why Jon Olson put so much effort into building true table top jumps.
Third, landing in pow, not that fucking easy at all, sure you're proabably safe from serious injury but pow landings are not as forgiving when trying to ride away clean, especially switch, think Sammy and Sean's cab 7's. Also you get fewer hits before the landing is bombed out, so maybe 1-2 warm ups to gauge speed/kick/inrun (after all you built it, it may not be perfect) then dial 1-2 tricks you have in mind in the next few hits.
And none of that can even happen until you exhaust yourself on a sled, and sweat your bag off to build a nice booster and inrun all day.