What he probably meant is that characters with unlikely sequels were given less priority. The Ice Climbers were probably seen as too time consuming to be worth the trouble, and development time is a limited resource.
Also, Kid Icarus is currently quite popular in Japan. Popularity is a factor.
As for
, he, like
and
were originally planned as alt costumes but got promoted to separate slots upon given slight differences. Sakurai has stated they weren't time consuming and lesser effort was put into them in order to avoid balancing issues when editing existing characters/assets. Something that makes perfect sense from a developer's point of view.
I have enough experience on computer programming to know what I'm talking about when I come up with the developer's perspective.
Well, Punch-Out!! Wii was developed by a Western studio, Next Level Games, so it makes sense the designs are Western styled. Even his trailer was in comic book style. Contrast with Palutena's anime trailer. Also, note how Japan reacted to him: they had little to no idea who he was and was pretty much a WTF character for them. Some did acknowledge he was more notable "overseas" though.