Phantasialand on the whole is generally a great park and one of my favourites. A lot of their rides such as Taron & Chiapas I consider masterpieces in their own ways.
There is definitely room to improve the offering further and a lot of it comes down to the entrance setup and older attractions. I think China might be getting redeveloped next but the entrance setup is definitely a challenging one as Josh’s points mention.
As for food, I consider it arguably the best park for food, from quick service to sit down restaurants. I do recommend Rutmoore’s Tavern if you return or the ice cream place near Chiapas if you fancy a snack.