I think "larger quadrants" are one of those things that is going to be in. But, I doubt that they will be THAT big...
I totally agree that quadrants should be bigger...
But...I was just about to also write that it seems to me that it would be very unusual for someone to want to play in a game with 250 Million systems...*however* I just realized that the coolest use for such a thing would be to provide a "real-time" background universe for role playing. For example, if I was still GMing space opera RPGs, I would use my empire in a certain game as the backdrop for it. If one wanted to run a "realistic" Traveller (or whatever) RPG game, one could set up an SE5 game in the largest possible universe and run a turn in it every time "RPG-time" advanced...that way, you could use SE5 to provide your RPGing with a living, breathing background universe...that would be nifty as heck.
Hmmm...the possibilities are pretty vast, especially once you factor in modd'ing...
I might ust get backinto RPGing if ultra-large SE5 universe come about...
-Alarik