Some games have to be steep. You leave POTC anywhere near 6.5 and it's going to be a bottleneck. Jack it up and it's fast, but still fun. I'd rather increase pitch to make a game harder rather than risk a too tight tilt. Players get mad if you make the tilt too tight. We've all seen it.
Yes, good players can sometimes take advantage of steeper pitch on some games, but the ball will always roll down to the flipper (or outlane) faster when you increase pitch. Agree on slings. Should always be touchy.
Tilt or pitch, it's a fine line. Test, test, then test some more.