Foreign languages are the most boring subjects

Essentially what you've conceded here is that foreign languages are boring until they're mixed with another subject such as history, whereupon they become more interesting.

No I'm not really saying that. I do two languages at degree level and I much prefer the language learning side over the culture stuff as once you go a bit deeper language wise you really do start to learn about and understand so many different things (not to mention the experiences you gain from learning them, the friends you can make from around the world and the proven cognitive benefits). However so many people think learning languages is simply just memorising a load of vocab when it isn't (although unfortunately at GCSE it pretty much is). It can be hard to motivate people to carry on taking languages post GCSE level due to reasons above so mentioning the more ''interesting'' aspects of it will hopefully encourage people.

What exactly changes between GCSE, A-level and uni?

I can't imagine it being anything but rote memorisation with perhaps a different amount of history sprinkled on top.