I agree. Whatever the next update is, it won't be a major one like the iPhone 4 was. I'm anticipating a slight speed bump, maybe a capacity bump, and hopefully a white option. I don't think we'll get the dual-core LTE phone people are expecting until 2012.
If there is one common theme on these forums it's high expectations only to be let down on announcement day. I believe you are correct.
Chances are anything that comes out this summer won't be big enough to disappoint the vast majority of Verizon users who purchased the phone in February. The new software, of course, will be available for all the later generation iPhones.