I don't quite follow this part. Could you elaborate? Unless I'm misunderstanding, I would think the fact that we have tons of tournaments and lists is one of the reasons it can be so hard to get people to participate: a lot of things are vying for their attention.
Whatever the theory, though, the reality has always been that it's taken a ton of work to get a usable number of participants, and that we can safely assume more steps (and more work) will lead to a drop in participation. Whether or not that's acceptable is an abstract question, but I think it's clear that this would be the trade-off.
What I'm saying there is that people are very involved with tourneys, tops and lists there and their dynamics and deadlines. This is not something new to them and I don't think that adding one round would make them lose interest. I do expect a drop in participation as well, but I can also expect people joining later, and in the end some balance. Anyway you can also see this as an addition to the current top format, to further explore, or try to fix, the bias of popularity. As said, they are independent voting processes.
@MissVicky
"But people aren't going to see it that way. They're going to see it as "If my vote's only going to count for 25% of what this other MoFo's vote is going to count for, it's not worth my time or effort.""
With that reasoning, people would have never voted obscure or less popular stuff on their lists at all. Why bother giving 25 points to this masterpiece of Somali avant-garde animation if I'm going to be the only one? Since I can't push it to the top100, my vote is futile.
Do people participate in these threads as a kind of competition to get their favorites there at all costs? Or do they participate because they are interested on building a collective list?
"But that specific premade list is still 100 movies and if you've only seen 25 of them, that's 75 movies you have to watch in four months to get your favorite to count for as much as someone else's - while still participating in the "Gazillion" other lists, tournaments, games etc. and still watching the unrelated movies you want to watch and... you know... dealing with non-movie related real life stuff like work and family. So again, if I'm someone who's only seen 25 of the "pre-set" list, it's not going to seem worth my while."
Again... so? That depends on the amount of time one decides to devote on it. Four months is, I think, a decent time length, but this is debatable. It can be longer or shorter according to preference.
Your argument of "dealing with other tourneys, lists or non-movie related stuff" is something so inherent to whatever activity we organize in this forum that I think it doesn't take place in this discussion at all. I can't say I see where you want to go with this. The same can be said for this one and the decade tops, the Halls of Fame, the tourneys... They all imply an effort and an involvement that some people will be able to bring and some won't.