See, I'm one of the people who writes long-ass justifications by default. Even when it makes no difference, since spends often include things that don't come up in daily RP (my character goes to the gym --> his stamina increases) I like to sit down and actually put the process in words. And since I ST, it's not that big a deal to swap plots with someone else.
What I intensely dislike is having to do it. Why? Because it's mandatory, it turns RP into a chore. It's not at all organic, you know? And it doesn't even serve a purpose - it's not like my roleplay will get better because I was in a hastily put together custom-made plot until a checkbox could be crossed.
I remember on HM when you needed a log to 'prove' you were taught something (or players might lie, as they do) and I was roleplaying teaching someone... I think it Spirit. The scene was horrible, the other person very clearly didn't want to be doing it so their poses were unimaginative as hell, there wasn't even a build-up. Neither of us enjoyed it at all. So why did we have to do it, who benefited from that?
Yes, if someone wants to play something out then by all means they should, it's fun! But the mandatory aspect of it, arghh. "Hey, can you please run me a Glory 3 scene?" is one of the things I don't like having to type, I hate asking for scenes - in fact I hate asking people for things in general.
At least - unless of course the 2nd Edition ends up changing how Renown works altogether - consider accepting justifications for the "act-dependent stat" portion of the exercise. 
</endrant>