A PA28 is a b*gger to get in and out of, and I am fit and flexible. Also it has only one door, which is questionable for emergency escape reasons. The door has two locks and if either jams (which I had once) you aren't getting out in a hurry.
I think a C172 is easier for me to get into and out of (6ft, overweight and not as flexible as I used to be) but a lot of that is due to practice. Getting inexperienced passengers into a C172 is difficult. However, I think getting them into a Warrior (I've not had passengers in one yet) would be much easier - it seems to be designed to make the pilot access the most difficult.
I agree with your view on emergency escape - that was what made me a bit uncomfortable in a Warrior first time round. On the flip side, though, I'd much prefer to be in a water ditched Warrior than a C172.