hmmm... I've given this alot of thought.
I really want the game's ending to be factor based, a few examples like...
Killing Richter Early for bad ending
Not saving everyone in OOE for bad ending
Defeating Maxim in Castle B without Bracelets for good ending
and so on.
Time based may be a mode for speed-runs, but not for main story
Completion based isn't really all that fun when you discover 1 hidden room held your ending back.
an ending based on factors would be best for a more story driven element.
but honestly, I haven't finalized any ending factors, and I am open for suggestions and such given the thread topic.