Getting a little bit of MR helps, but Akali going just Q and R and not proccing the mark won't do much damage, unless she is super-ahead, then it doesn't matter if she procs her Q or not, R's base damage is insane against a squishy.
Its much easier for Akali to bait out the Q knockup and windwall, since they both have long cooldowns then jump onto Yasuo and then its gg. The Q knockup should always to saved to counterattack her when she tries to all-in. Akali is a snowball champ, so her sitting back and just farming isn't doing herself a favour nor for her team.
But Yasuo is a damage carry as well, so he can easily pop Akali as well. I'll say its more of skill match-up because I have vs'd against Yasuo's that know how to play him and make it much more difficult to all-in him.