Creating a query is major part of the day to day activity of integrity users, and we do come across situation while creating queries wherein we would have to swap AND with OR and vice versa.
As we do not have the option to swap AND and OR we are forced to remove everything and do the entire query from scratch. We do have the swap button available in other places like;"Set notification", Field Relevance rule, constraints and also also while creating Trigger rules.
From user's point of view it is necessary to have a Swap button in query definition view as shown below:
I agree completely.
However, you have posted this as a discussion/question topic. I suggest you re-post it as an idea. This way it could be voted on.