A full story with an end would be nice, but leave the future open for more adventures. A cliffhanger might be a little too optimistic. A first season that ends on a cliffhanger can often cause some regret if the show gets cancelled. Better to save that kind of thing for a later season, I suppose.
I just feel like while they introduced the magical pen, there isn't really time to use it properly this season, so they should just do something to tease it for season 2 (if it comes to that). I'd rather see the Shining Knight actually used properly since they have spent more time setting him up.
Wonder if Mikey can get the Imp to resurrect Brainwave Jr then?