35T teams that have 1* players who perform well play them in serious matches. My 3rd team @level 5 has a non-SA striker playing in a counterattacking team who has scored 77 career goals in 128 matches, including the Cup Winning goal.
Any favouring of low star players in the rankings imo will be relative. It will depend who they are up against. If there is a chance to be better rewarded it will be balanced by the quality gap that makes it less likely they will do enough to actually get it.
I do not believe and have not seen automatically higher ratings for low star players but I have seen very high rated 1* players, just like I've seen very high rated 7* players.
You really won't get any proper proof....better to forget proof and go with 'feel'. I might do some friendlies between my 2 levl 5 teams over next few days and compare ratings....if not I'll post some 1* player ratings after a few games.