In my opinion Klonoa Heroes has the best story of all the Klonoa games. A lot of character development for all three of the main characters and a good look at parts of Lunatea we hadn't seen before and a nice revisit to those we had seen before, and a theme of heroism which gets the player thinking. That plus the fact that they "killed" Klonoa (I swear I cried when I got to that part because it was so much more unexpected than even the death of his Grandpa in the first game) really made it an exciting watch (I watched it on YouTube because it provided the English translations in the cutscenes) that really didn't get the gameplay it deserved.
And honestly the gameplay wasn't too terrible (I started playing it after I watched it so I could understand some of how to play) or uncomfortable to adapt to. Yes unfortunately things get pretty hard at the end and there was a lot of annoyance between having to handle multiple enemies with different bullets and bombs and I do not doubt at all that the gameplay could be better. This game NEEDS a remake because this story deserves some revamped gameplay (I think it could benefit from some 3D engine, too).
Unfortunately the reason it wasn't released in the U.S. leads me to believe that even a remake wouldn't make its way here. America didn't want to soil a kids' game franchise with references to alcohol and swearing, and it is pretty dark compared to the other games. Personally I wouldn't want it censored if it was brought over here (I really don't like it when people censor art forms unless someone has actual malicious intent) but I'll take what I can get I suppose...