For whatever it's worth:
I've lived about a long walk from SBU almost 30 years now, and frankly not a whole lot has changed dramatically with the university and surrounding area in that time. I'm sure others of you agree. And where we might disagree is, I think that's a pretty good thing.
I have mixed feelings about our town and environment and all associated things. On the one hand I think, yeah, wouldn't it be great if the nearby Setauket/Stony Brook area or SBU campus had a bit more life--restaurants, bars, music, etc.--instead of feeling deeply dead and quiet, with quite a few boarded up storefronts (esp. in Setauket at the moment). A lively "college town" like the places my kids went to school.
As is the case in many communities, SBU and various surrounding constituencies have pushed for further development at various points in time while I have lived here. Most (at least the big ideas) never happened. Did you know, for example, at this moment in time there is a MAJOR push by owners of the nearby-to-SBU and mostly undeveloped Gyrodyne property to do a huge development on that land, including a hotel, medical park, and other businesses? The proposal calls for a single road off the property from all of that (hundreds of additional people/cars every day) onto 25A. How do you like that, neighbors and drivers on 25A? This proposal (and other big ones in the immediate area such as a big, new assisted living facility on what was open farm land) are moving through the Smithtown Board right now.
But let's say you like these ideas. Progress ahead and let's do more! Well, another big issue is sewage. Want more student housing at SBU? There is a huge difference between a single student/human driving to campus and maybe flushing one toilet that day vs living on campus and flushing a bunch of times, showering, etc. Multiply that by all your new resident students, and you get the idea. We people make a mess, and it has to go somewhere in its semi-treated form (and let's be honest, there are always untreated events that happen). Where will it go? The Gyrodyne proposal and other similar development proposals in the area call for a big, new treatment plant adjacent to SBU (can be smelly when the wind blows in your direction), new sewer lines (vs smaller cesspools currently used in much of the area), and a plan that will send all this new waste, either indirectly or directly, into Smithtown Bay/Stony Brook Harbor. Like to clam/boat/swim/fish/hang out and breathe fresh air around those mostly clean waters in the summer? That will end or be severely compromised.
I'll climb off my soapbox now. Point is, and this is certainly obvious, these things are complex and can have a significant impact and change the character of our area. Worth talking about, yes, and debating, but you just have to be careful what you wish for, methinks.