Overwatch literally has a Gold/Silver/Bronze medal system at the end of matches which would be a godsend to XIV PvP. Not even a hard system to put into Frontlines; Chocobo Racing already has an emblem for Gold/Silver/Bronze, and the Frontlines results page already lets you rank players contribution.
A correction, I put damage in there when I shouldn't have. Base the tally purely off Kills/Assists/Objectives (Ice/etc.), with Deaths being a point against, although I'm not too sure on that point. For a medal system count damage, but somehow I doubt a healer would rank high enough for that to matter.
The game already tallies these statistics, it's just a matter of applying a value to them instead of overall placement. Various ways that can be done too, I'd rather not forgo a reward at the end, but you could reward players per Kill at the point of a Kill, which is really no different than how PvE works.
Sure, I just don't find it particularly rewarding. Rewarding the overall result, which you can put absolutely any amount of effort into and still receive, just wont feel as rewarding as rewarding individual effort, IMO. It wont encourage the same level of individual improvement, because it's a team game with increasingly limited control over your team. There's still going to be people who come in and "ruin it" for people, and that's going to discourage people from trying. Why put that effort in when others are going to undermine it, after all? At least if you reward individual participation, you always have incentive to keep trying for you own sake. That hopefully ripples down and improves the overall quality of players. Continue to reward simply getting carried? People will continue to simply do no more than try and get carried. Someone who actually tries will have a higher win rate of course, but so long as you can put effort in that goes unrewarded, or put minimal effort in and get rewarded... The majority of players are going to take the path of least resistance. Rewarding randoms for being on the team with the most premades doesn't change their attitudes at all. Punishing players for putting effort in when they get teammates who just feed doesn't encourage them to keep putting effort in.
If we're talking cost effectiveness though, SE already has their solution; Ignore NA/EU completely. JP has a different culture going on which mitigates a lot of our issues, so our issues don't even exist to begin with. We want something fixed which JP doesn't need fixed. Look no further than "Hello" for proof; NA/EU want a specialized "I'm Ready" quick chat function added, the JPs client "Hello" translates closer to that already which is why it's even used that way to begin with. Since they don't need an "I'm Ready" quickchat, we don't get one, despite it being a frequent suggestion and requiring very little work to actually implement. They could even just change the localization of "Hello" to "I'm Ready", but nope... The localization team would rather throw another Beta Wolf on us. That title being another case of "Well, it's not an issue in JP... So...". Rival Wings need a Roulette to help with pops? What do you mean, it's frequently active on JP, no adjustment required. 24 player Frontlines? Not popular in JP so say goodbye to it, doesn't matter how popular and necessary it is here.