I didn't speak about hard fights, I spoke about challenge, born from depth and complexity. I would also like sidequests (and everything else int he world) to seem organic and unified, not--like my example in the OP--a makeshift addition, all seams and clumsy design, if there was any design at all.

I don't have anything about a casual game, on the contrary. I just don't think we should slack the vigilance about laid-back design, rushed design and boring game structures, whichever they might be.