White → Kill 10 random Naga.
Blue → Kill Naga lieutenant.
Blue with dragon portrait → Kill Naga captain, and bring some friends.
Purple with dragon portrait → Kill Naga commander, and bring some friends.
Pet battles have difficulties too. The rarity which dictates abilities and stats is represented by color:
Grey, white, green, blue, etc…
There’s some logic here to the way Blizzard have designed it. It’s intuitive.
Logically, a world quest that’s white would dictate a low difficulty for the particular task (kill, fetch, cook, collect, pet fight, puzzle, etc.) along with a low reward.
But Blizzard have chosen to put in the highest difficulty (for pet battles) for a normal world quest.
So that’s critique #1. This breaks their own design, because it doesn’t follow the established rules.
Critique #2 is that the highest difficulty of their pet battles breaks their own design as well, because the legendary debuff doesn’t follow the logic of more stats and abilities gained. It breaks the design space, which has a negative consequence on the gameplay (you can only use certain strategies to win, because the debuff dictates the gameplay, not the type or stats of the pet).
I don’t think they are hard, but rather bad designed. They have 0 logic. You can miss, but nowhere do you see something about a miss chance, or how you can upgrade it. It’s just a mobile game of chance. Very boring and I’d rather have them not invest lots of time in pokemon.
All pet World Quests are marked White. Which is appropriate, because they are all exceedingly easy for anyone who has followed the series to BfA. The most difficult battles in BfA, after Fras Siabi, which is a special case in the STratholme instance, are Not Too Bad Down Here and Captured Evil. Compared to those, the “cheese one orange opponent pets” are trivial. White is the right colour for all of them, by this logic. So, as you say, that deals with critique #1.
Again I say, the legendary singles are not the highest difficulty. You say “the legendary debuff doesn’t follow the logic of more stats and abilities gained”. That’s a criticism of the Boss buff, not of the battle - and I do agree somewhat. The Boss buff would be fine if used on special occasions, but they yank out out for nearly all single-opponent battles, and it got old after Mists. Not so much a breaking of the design space, though, as a piece of laziness in not thinking up new mechanics.
How are they hard when there are a few sites that have guaranteed strategies to win? It seems as if you either do not know about the sites or do not have the required pets to win matches.