Slovenia is lovely paddling, you can learn loads there if you push yourself as demonstrated by the guys last year, it's a pleasant spot and in my memories quite warm. But is expensive to get to.
Val Sesia is a lovely spot, but I will say this: I went out when I was a solid level 4 boater, doing level 5 training and I still found it very intimidating. Even at that level I was limited in what I paddled because I was not good enough to get on a lot of the rivers and often reasonably nervous even on the ones I did. It is amazing, I want to go back someday, but I think unless you are a very solid level 4 boater with a bit of experience you will be limited in what you can run.
France would be somewhere I'd love to go back to but every time I try the water levels go mental.