Combination of filters using and, or, xor, not etc.

I think there are two concerns here:

1. There is no XOR in logical expression, and to achieve it would be writing a much more hefty case statement.
2. Want to avoid overloading calculated columns with a logical expression where possible - such a column may be meaningless to many other visualization tabs; however, per visualization may be too repetitive to implement, if there are multiple panels that should have the same logic either.

You can create more complex filter conditions by inserting a calculated column with a logical expression.  E.g. if you add a column with the following expression ([Department]="Finance") Or ([Employee Status]="Contractor") you will get a filter with the values true or false that allow you to filter out or filter in all rows that satisfies your condition. 

It´s also possible to limit what is shown in a specific visualization by using a logical expression similar to the one above. 

Yes this would be nice and it would be great to be able to switch between AND and OR.   Users sometimes want to see when all filter  conditions are true rather than if any are true.

I'd love to have this. So many times we need to filter out only a specific combination (e.g. filter out device 4 but only on board 2)