Fire away. I probably get what you're saying, but I try not to make too many assumptions there, as I am pretty thick-headed.
Okay. I was a backer of Scion 2e (because I loved the concept of 1e, but it had problems on its problems), but when the Storypath version came out, it had a couple of big problems from my POV. One of them doesn't related to this in general, because its its at least partly, probably mostly a taste issue.
But then there's Momentum.
Now, to be fair to them, they do somewhat recognize the problem I'm about to discuss, since they present an alternate version of it that doesn't have it. But its one of those sort of tucked-in-the-optional rules things that people do when playtesters have told them something is a problem but they really don't believe them. It should be emphasized right out the gate when Momentum is brought up, because its potential problem with a lot of groups, and a really serious one for some.
The issue is that Momentum is a group resource (as I recall, if you're not familiar with Storypath, I think if I'm not being confused, the Modiphus 2D20 systems usually use something similar--might even use the same name). This has two potential problems that can come up with it, and because of the nature of the problems, will probably in a lot of groups not get talked out until its exceedingly obvious the problem is there.
1. On one hand, some people will tend to use Momentum any time its even vaguely useful because its there and they don't like to fail. The net effect is that other people don't effectively get their share of a resource
they've helped to generate. But there's no obvious metric to "how much is too much".
2. At the other end, some people will be overly conservative about using it because they
don't want to hog the Momentum, to the point of not using it the way the system expects you to. While some of this can occur even when its not a group resource, its less severe since they're only worried about their own future needs, not the groups.
Its not even going to be particularly uncommon to hit
both in the same group, which makes the matter worse.
Now is this going to be a problem with every group? Of course not. But I think its not illegitimate to claim that people mostly experienced with groups with a greater cohesion in how everyone supports everyone else in the group are going to not think of rather large numbers of people who aren't quite as good about this. And some of those people are game designers, and I think they tend to either underestimate how common this sort of thing is, or (and this is far worse) just think its not their problem.
I'm fortunate that I'm with gaming groups that are older and self-aware enough that we looked at this and said "Yeah, that's trouble looking for a place to happen" right out the gate, but not every group
is, and I think warning signs are simply good practice for that reason. And this can apply to all kinds of things, some of which I quite like, but have enough evidence to know is a minority view on.