>They would still have to think of these ideas in order to test them.
Text has background, envelope, whitespace (leading, kerning, etc.), font, outline, fill (and probably other general properties too). It's not A/B testing but I could see engineers iterating over variations - should the envelope follow the curves of the text or be a box or blob, etc.. All spacing, be it kerning or border-width can be iterated over, colours too - indeed thinking of this makes me want to write an Inkscape plugin to help in font choice.
You can level your objection again but I don't think one would call thinking what shape an outline could be "design" per se. Indeed if you're just presenting alternatives to a user and looking for the one with the best feedback I think you arguably have done away with a design stage.