I think that depends more on you as the player. The only reason I can say that is because of your stream last night. You were using something of a stall team, which means you weren't hitting hard enough in most cases to counteract their healing. If not for your Kricketune I doubt you would've made it as far as you did, as soon as you did. Whereas an aggressive play style, like the one I use, doesn't have a problem with the small heals and by the time they use the big heals it's too late (I actually try to force the AI to use there heals on their first Pokemon which usually isn't their ace) and I can already beat them.
Now the field effects are another story, especially in the early game where the players options for teams are limited. The field will almost certainly have their way with you (looking at you burning field!). Countering those can be a lot less easy unless you study the field effects (which I will never do). However in most cases (glaring at you burning field!!) it's far from impossible. Fights like Arceus are false difficulty in my opinion. But still beatable.