I think that the true utility of a course outline is in putting it together. I generally set up a bunch of tests and rules, trying to synthesize the case law into something that I can actually apply to a fact pattern -- cases get filled in as illustrations of a principle.
My outlines tend to be longer because of how I organize my exams -- thesis, then rule statement, then explanation of the rule, then application of the fact pattern to the rule, then restate my thesis. Organizing my outlines by rules allows me to quickly and easily regurgitate what I've already synthesized back into my exam, with helpful cases that I can use as illustrations and comparisons to the exam facts. So this semester, my Adjudicatory Crim Pro outline was 75 pages, while Ad Law was 40+. My Ad Law short outline was only 15, and my attack sheet was 3.
I tend to write long outlines first, then I break those outlines down into shorter attack sheets or checklists, which is what I actually use on my exam unless I need to discuss something more thoroughly. I'm one of those people that goes into an exam with a binder full of multicolored tabs -- a lot of the time I don't need everything I've prepared, but I'm always happy that I have it when I DO need it.
Anyway, the point is, it doesn't matter how long or short your outline is, as long as (a) it contains all of the information you need to dominate on test day; and (b) you can actually USE it on test day [organization is key].