That's the problem with house rules. They often sound good on the surface without necessarily actually solving the problem or in some cases, creating new problems.
What is the point of choosing to school me on this? Considering the entire point of the thread is examining the potential problems of a house rule, your quoted text comes across as condescending, though I hope that was not your intention.
I thank you for the math example. It supports the purpose of the max damage suggestion, which was meant to limit the usefulness of a "skill as a save," so that it was less desirable than using your normal weak save--except during those few "go big or go home in a box" moments.
For instance, if you know that 28 damage fireball is going to take your character out, would you rather have a 60% failure chance for a weak save, or a 30-45% failure chance by using a skill as a save in a creative and narrative engaging way? Using a skill in the place of a save every round, with the max damage limitation, you fight a losing battle to the law of averages--a battle that will probably be over pretty quick, too.
The failure of my suggestion, that your math indirectly shows, is that max damage limits the "skill as a save" too much. The usefulness of the skill as a save is basically locked into that corner case I chose to design around, which I originally stated as "dire straits" moments. I would like to see it used more often, which is why I'm not satisfied with the max damage limitation.
I am trying to find a way to give a player some narrative control and creative freedom during combat; the ability to use skills in the place of saves is a possible avenue. The big hurdle is keeping it relatively limited in scope to prevent excessive spamming. I don't see this as fixing a broken aspect of the rules, it expands the rules to include another aspect of play. I think this is where the major disconnect occurs between people coming in to this thread determined to dissuade the discussion and those genuinely interested in exploring the potential of "skills as saves." We aren't fixing something broken, we are adding something previously overlooked.