They are used in this way to try to make different feelings, like 'l'm loving this!' is like 'I'm really enjoying this so much', and 'I've been wanting to go' is kind of 'I've been excited/thinking excitedly about going' or something. It's just to make a different nuance and is quite normal in those cases. ('I've been loving winter swimming' seems general so it isn't the same situation as my example (really enjoying doing something at that moment', so it doesn't work)

The fact that they're stative verbs means that they aren't USUALLY used in continuous tenses, especially the past/present continuous. E.g,: ' I want an ice cream', not: 'I'm wanting an ice cream'. There are exceptions, though, and no rule is hard and fast. Remember Mc Donald's 'incorrect' use of 'I'm loving it'.

In my opinion, they mean the exact same thing. It's personal preferance. They can add a specific date or time period and they would still stay the same. "I have wanted to fly a kite for ten years or I have been wanting to fly a kite for ten years."

In my opinion, they mean the exact same thing. It's personal preferance. They can add a specific date or time period and they would still stay the same. "I have wanted to fly a kite for ten years or I have been wanting to fly a kite for ten years."