I'm sorry, the juvenile one here isn't Wave. In the least.
People asked what you get for the $150
Wave specifically laid out what you get for that amount officially.
Then some folks decided that it wasn't worth it to them. And nothing is wrong with that. But do you know what is juvenile? Acting like because you didn't get the answer you like then no answer was given. Acting like because it's not worth it to YOU, then that must be a universal truth. Having someone tell you plainly "this is what you get, anything more can't be guaranteed. Ultimately, it's an individuals choice if that's worth it or not", and then chiding that as unprofessional, is "juvenile" to me.
I see an individual who is trying to take all the feedback he's gotten (not simply the squeaky wheels of the forum), his own business sense and principles, and the realities outside of his control and is making as clear of a pitch as possible. And I see him being VERY professional and adult in understanding you can't please everyone and not foolishly making poor decisions in a vain attempt to try.
For those that get to regularly go to cons or regularly play table top, I can see the lack of appeal.
For myself, the DDXP is the primary reason I'm excited for Gencon after my first trip back in 2014. And it wasn't the "swag" that attracted me to it when I saw it then...it was the setup.
I don't get to play regular table top, especially with the busy I'm going to the con with who was my childhood gaming partner. The little I do is in a game shop with questionable at best DMs.
The idea of being with the same party, and the same DM, playing a cohesive multipart mini campaign, without the mess of muttering, in a comfortable environment, that isn't nearly as noisy and distraction heavy as the rest of the con, is a HUGE attraction to me and is absolutely worth the money TO ME.
Do I think it will be to everyone? No. But then, not being juvenile, I don't expect everyone to have to adhere to my exact same opinion.
Would some extra perks be nice? Sure. But not necessary, and I'd prefer to not know what they MAY be if they're not guaranteed as to not form a level of expectation.
You call it juvenile, I call it realistic. Wave is correct. This is the program. If you like it, you'll sign up. If you don't, you won't. If enough people like it that it sells out, then ultimately your dislike is of little impact...all it meant is someone else took the opportunity you passed up. If it doesn't sell out, then as a businessman he'll have to reexamine things and change it up. That's not juvenile, that's being an adult and a business owner.