Someone over on NeoGAF posed the question above a few days ago in response to the release of Kirby's Epic Yarn (below), which is, according to a number of folks who have played it thus far, a completely charming but not altogether challenging game.
My first reply to said question was an emphatic "no." After all, some of my favorite games of the last few years have been (basically) challenge-free affairs--games like Animal Crossing: City Folk and Endless Ocean, for instance.
I had to revise that riposte, though, after I remembered my unenthusiastic reaction to playing Super Princess Peach a few years ago. Sure, the game's graphics and tunes were enjoyable enough, but the rest of it was a bore due to its overly accessible (i.e., "so easy a newborn baby could beat it") nature.
Anyway, those are my (barely considered) thoughts on the matter. What are yours?