I realize that in general Square Enix is inexperienced with pvp and how to make a system that works, which is quite evident through the wild changes that happen in pretty much every patch.
For the most part I like to give SE the benefit of the doubt and try it out but there are two things that I cannot ignore and in the end will just become a detriment to the PVP community and SE's goal of making PVP something people want to play.
1. Light Party and rewards. As far as I can see it the only requirement to receive rewards in a team is to just be a team itself. So in theory you can just invite someone and they wouldn't have to play a single game in order to receive those rewards. The problem with this is that it will encourage the selling of extra spots to people who either have no business receiving those rewards in the first place or people who did basically no work with the team, receive rewards as well. I am sure SE already sees problems with people selling Ultimate clears by getting other players to play their character for them, so I also think SE should understand that you have made it incredibly easy for people to sell Light Party rewards to people by allowing the current reward requirement, which seems to be just being on the team.
My solution really is to require a personal rating. Your personal rating increases as the team rating increases, and you are required to be within a certain range between your personal rating and actual team rating in order to be eligible for rewards. You can also have it if someone is perhaps at zero personal rating while the team rating is at like 2000 rating that wins received will produce more personal rating that scales down as it gets closer to the team rating so they can catch up sooner.
If this doesn't happen you will see people selling spots in their light party team for real life money, and the funny thing is you won't be able to know about it since people don't need to share accounts to do it. So I hope SE takes this seriously.
2. Saving your highest rating. I can't begin to say how misinformed and stupid this idea is. It is rife with potential abuse, so much so I don't have to explain it that much. People can potentially get a high rating and then purposely tank their rating lower so they can prevent other people from climbing in the rankings by playing at the lower ranking. A simple example is a diamond player tanking there rating to plat and purposely prevent others from getting diamond by playing in platinum when they are actually diamond level, guaranteeing their own win while giving others guaranteed losses. If rating/rank is not risked people are free to abuse the system to keep themselves safe. You create a toxic environment if you go through with this change, please do not do this. People have asked for rating decays forever, yet you pick this horrible alternative. Just don't do it.
SE please reconsider point 2 and please find a solution to point 1. As it is right now you are basically asking for people to abuse the system in a unsportsmanlike way. If you truly want this game to have some sort of esports potential get rid of avenues of abuse that you basically end up ENCOURAGING.
Thank you for reading.