If I may add, it is actually much better to fight as a non-DA if the CHALLENGE is what you're after; once you unlock all the rest, it can be too easy. It makes you stay on your toes and actually think about your next move.
In fact, it's more satisfying because of the victory over the extreme difficulty. Sure it was annoying for me when the Sporca was released (it almost make me quit really), but I willed it a bit more and now I have little Sporcaling in tow (dat cute lil guy <3).
Time was never the essence of the challenges, which is kinda ironic since the challenges are at the Inn at the EDGE OF TIME. Then again, time seems stopped here, so take as much TIME as you need. You may not complete it now, but if you experiment, you might happen to have a strategy that is surprisingly effective, despite looking stupid. ever heard a normal Chicken Cow defeat a Leorilla, using a massive amount of Mad ChickenCow Attack? Take a long, long time, mind you. Now I just need to deal with the Omae wa Mou Shindeiru...
So, in short, they're not impossible, just quite infuriatingly difficult. THAT'S the challenge. Can you keep your patience?
Otherwise, if challenge is not your thing, it's your choice whether to play it for the lulz or ignore it altogether, which includes foregoing the badge and/or the rewards. If you think about it, if you really want the reward badly, you'd put yourself in that despite how it makes you want to smash a keyboard or fling the mouse to a nearby cat. If it's not worth the effort and frustration, why bother? And while this means forgetting about the reward, there shouldn't be regret, because you will have to weigh in effort vs reward. This is why I don't bother with the Meowphant in this case, because I would prefer the Leorilla Mane Belt IV over that. I play it once in a while, just to trigger the Meowphant, but not as much as to try to defeat it. But since I want the portable TogSlayer armor (I'm quite lazy adventurer and prefer to have stuff with me than having to go elsewhere for a piece of armor, besides, I wonder how the re-skin looks), I grind.
Now as for the chain-skill classes (Warrior, SoulWeaver, etc. ) indirect nerf, I do agree with Eragon Dragus with the shield bypass crits on the last hit. After all, it's still a LAST HIT and Crit means that it hit right in the kokoro (therefore a hit, basically), even if the other hits were dodged in a way like the mosquito from One Punch Man (the only critter that Saitama can't kill, apparently).
Sorry for the long post. BTW what do you put here in place of a potato or banana?