I don't know what you expect? Bugs exist. Even with pest control bugs still exist. Yes, the airline needs to do their best, but how do you know they didn't do that?

Don't mean to sound harsh, but seems like everyone always "wants" something everytime something out of the ordinary happens to them. In this case, it sounds like the crew accommodated you with a seat change, seems reasonable. I wouldn't expect them to give you a ticket or miles, or anything beyond that... Just my 2c.