Wonderland has changed in many ways since I was a kid, and in other ways hasn't changed at all. It's still fun, still makes my head pound from all the skull-bashing rides and still a good way to spend a day!
Some new(ish) features - fast pass. For $70 you can get a fast pass which basically allows you to skip the line. You still have a line but it's more like a 5-10 min wait max instead of who knows how long. Not worth it in my opinion, but if you have cash to burn, why not.
Preferred parking - you can pay $25 (instead of $20) to park closer to the gates. It is significantly closer ... But I'd rather save my $5. When I went back to the car to change out of my wet clothes from the water park, I simply moved it closer as so many people had left already.
Water park lockers - now $15 (they used to be $10!!!) and done digitally. Frankly a much better system than the old key around the wrist method, but we had some trouble reopening our locker several times.
Gluten free food options - oh yes! Finally wonderland caters to food allergies and restrictions! I was able to order gfree chicken fingers and fries, and there were also options for burritos, pizza and stir fry. I was pleasantly surprised! Food is still expensive as hell, but it's wonderland. What do you expect?
I don't know how new or old some of these things are since its been a long time since I visited. Leviathan wasn't even built yet and paramount still factored into the name (and the names of the rides). But it seems like wonderland is trying to hold their own against the American parks with all of their new fancy money-costing perks.
Whatever. You can still have a great time whether you pay for the upgrades or not!