I think still having a deadline is a good idea, since, If your RR is good enough, you can bee in an unlimited number of games. I could see myself putting my name in the hat for a Haven game one week, and a gobble earth game in another week, and a Chaos Game on the third, leaving them there for months, holding out hope that one of them would eventually start.
Imagine my terror if, by some happenstance, all three games actually got off the ground at the same time. Suddenly, without realizing the corner I had backed myself into, I am in three massive games that I have no chance of maintaining.
I guess, without deadlines, I'd just have to adjust my buy-in habits to only join the massive games when they're just about full, rather than throwing my hat in at the very beginning to show my support. I would just fear that the "New game" section of the site would become a languishing wasteland of 6 month old Chaoctopi and WWIV games waiting to start.
TL;DR: I think longer deadlines is good, but no deadline is bad.