1 - An opportunity to meet and learn from experts in SQL and learn about new features in the Microsoft data platform
2 - An opportunity to talk to other data experts (DBA's, database developers, database architects, etc) from all over the world.
I agree with ideas 2 and 4 for sure, but I'm a little hesitant on options 1 and 3. Having the Summit move around means I get to see more of the USA (and potentially the world) as I attend. And I really like the idea of more networking options, especially some that are sponsored by PASS. I know at past PASS Summits, getting to some of the events required you to talk to the right person to get an invite to an event. These were usually sponsor funded events, so it made sense to keep the number of people attending a bit lower, but I would just like to see more PASS sponsored networking opportunities that don't detract from conference learning.
Option 1 means that a lot of people who want to attend won't be able to as it could sell out before their employer can get all the paperwork in place. I know at my workplace, it can take me a while to get the approvals for training and travel for something like PASS Summit. If the cap was 3000 people (for example) I then have a higher sense of urgency to get the paperwork and approvals through that may end up just getting denied or missing the target for those 3,000 people.
My concern with idea 3 of having more summits is people may be less inclined to travel to attend as a second Summit may be closer to where they live. This is a good and bad thing. Good because it may mean cheaper (or no) flights and hotels, but it may also be that getting speakers for the events becomes more tricky due to them not wanting to travel to potentially speak to an empty room. I think if option 3 goes forward, it would be good to have the different Summits more focused on a specific technology or target audience. Like have a Developer Summit and a BI Summit and a DBA Summit and so on.