It's nobody's interest to have sessions in the limbo, and if a session looks really weak/off-topic we can discard it asap. The hard deadline on July 3rd also looks unrealistic, specially compared to the casual setting we had last year. I understand some of you want something with more structure but closing the call for papers 4,5 months before the event sounds almost like an academic convention or a business fair.
Proposal to reword this: July 5th and September 13th because they are Sundays and people tend to do a lot of weekend work when submitting proposals in these kind of events. You avoid any timezone misinterpretations looking at whatever has been received before Monday morning European time.