There are plenty of enemies (coming quite soon for you in act 2) that have permanent evasion.
My guess is that is to make it impossible to run a physical only team. I have 2 lone wolfs - Lohse as an Archer (only physical) and Fane as inquisitor (magic only except for some necro). Quite a lot of fights Lohse has to sit it out. She does more than double the damage but that is no good if you miss 100% of the time. She can't even heal Fane (as he is undead) so I just leave her at the closest shrine to watch (and resurrect if needed).
I think it probably is intentional - it is common for enemies to have other immunities in tactician (fire or air or poison or whatever).
