Product and to a lesser extent Bagel are interesting cause there are many paths to the point or the many different positions that can influence the point. I think this is a big reason clearcut wasn't too successful, the only meaningful positions to influence point are from being on top of a shed, inside a shed or being on the floor in front of the point, and it's all pretty Clear Cut what classes excel at playing those positions (soldiers are good indoors, demoman can sit and stare at point and tag guys on shed, scunts love height).
forward holds are also a big thing. I think strong forward holds are somewhat alright if the trip from spawn to attempting to break it is short (product forward is strong but at least u arent walking for 10 hours through a massive lobby). Ideally, you avoid a super strong forward hold and allow for teams to take aggro positions that they have to be forced off before a normal fight on point.