What if Tank classes could only meatshield?

[Rhais]

Now I ask:

Should damage still exist but be trivial amounts in the grand scheme?

You still get your feeling of 'reward' from doing damage, but the design would shift to you completely catering to your party members and boil down to you hoping that they can beat down that pinata before you get tired.

There is no reward when you know what you are doing is inconsequential. It's rewarding and enjoyable to have the option to make meaningful contributions to the primary goal of the party (bringing enemy HP down to 0), while still carrying out the responsibilities of the tanking role.