Dave,
We have an E30+, and my wife occasionally suggests we consider buying a larger boat for the times when we sail with adult married kids or another couple, which we do fairly often. While a bit more space, including storage space, would be convenient, I doubt we'll buy a larger boat. The main reason is that I singlehand quite alot and at age 59, I can manage this boat nicely--raising and flaking the mainsail, snugging jib sheets, reefing in a blow and bringing her into the dock and stopping her if I have slightly misjudged speed, wind or current at the marina. I'm not sure that I could do all this with a larger boat, especially when I'm a few years older. I definitely don't have the same strength as I did when I was 50, despite healthy living and regular exercize.
While you can't really buy a boat now with strong consideration to whether you can manage it 15 years from now when you are 65, it may nevertheless be worth thinking about how you will use this boat, whether you will sail her yourself, and what size boat you can manage when the winds pick up unexpectedly.
Good luck with your decision!
Frank