Restrain character walking angle

[StillInThe90s]

Hey folks.

Problem:
I have been struggling with my character 4-way walkcycle and come up with an acceptable one. Everything flows nicely as long as the character is facing left, right or is walking in a straight vertical line up-down. As soon as it starts walking at an angle, facing up or down, everything turns into ice skating. Walking at an angle facing left-right still looks ok.
Adjusting animation/walk speed or removing/adding frames does not really help.

This is a common problem, I know, and many people does not really care about dangling legs but I think it ruins the game slightly.

So my question would be: Is there a way to restrain walking angle while a character is in loop "up" or "down"? The way characters walk in Beneath a steel sky or Simon the sorcerer are the best examples I can come up with.

edit: http://www.adventuregamestudio.co.uk/yabb/index.php?topic=42720.0   Brings up sort of the same issue, but not quite.