I went to leaky for the first time last year, and I still loved it. I see what all you are saying about it deviating from being an only HP con, but honestly I really enjoyed the atmosphere it created (LC is also the only con i’ve ever actually gone to so that also could be affecting my perception). I went to a panel last year, I don’t remember what the actual name was, but one of the main things discussed was how the con was expanding to include all of these other fandoms. The point they were trying to get across was that while there were these other fandoms being represented at the con, what was supposed to be linking the interest is the love of HP. The first fandom I was ever a part of was HP, and I think the reason I grew into loving other things just as intensely is just a part of my personality. However, I wouldn’t have really grown into loving and participating in these other fandoms without first doing something similar in the HP fandom. So for me, being a part of fandom period began with HP, so in my mind, having LC expand to include more fandom related things is really awesome and it makes sense because I started with HP and the expanded into other fandoms.
I do totally agree with you on finding it weird that people are going to leaky just for the park event. It is definitely not what the con is about. As someone who really wanted to go to the park event, but didn’t get a ticket, I understand that it is frustrating, but honestly, the park would have been (and hopefully will still be) an awesome bonus to an already amazing event.