It’s true, you should go either full magic, or full physical within a specific character, however a 2magic/2physical party is great as well since almost all the combat encounters will have a mix of heavy physical armor guys and heavy magic armor guys.
But really once you learn how the action economy works, as long as you don’t gimp your characters by putting dex on a mage or whatever, you can blow up most encounters regardless of the magic/physical make up of the party.
And of course you can also go lone-wolf archer and single handedly win all encounters on your own ;)