People actually paying attention to Feast PVP or PVP as a whole realize that lowering the number of buttons does not actually encourage new players to try out or stick with PVP. All it does is alienate players that actually enjoyed engaging gameplay rather than monotonous repeats of spamming the combo button over and over again.
The true mechanism that drives all content in this game is the rewards. And If you have been paying attention prior to the most recent patch Frontlines and especially Rival Wings have just been crawling along or just straight up dead content. Now with the release of a new mount, hairstyle, and other rewards people are actually taking a look at PVP. So stop the false talking point that a low amount of buttons encourages new players to try pvp. It is just wrong.
Within the PVP community even now balance isn't the first word that comes to people's mind when thinking of the current content. If anything the lower amount of buttons restricts SE's flexibility in actually making change without drastically changes jobs. A good example is Summoner which has been straight up bad for a long time and the way they made it "better" was by removing tri-bind and adding whither. So the only way to balance a job is by removing skills and adding others? Pretty sad to me. What is also sad is that summoner is still by far the worst job.
It also stands to reason that with fewer buttons that you basically make the jobs more "samey." How did they make White Mage better? they made it more like Astrologian by giving them a ability VERY similar to essential dignity while removing what made White Mage unique, benediction.
So nah, balance is still as broken as it was before, but you still have a gamestate where the only way to make jobs better is by making them similar to others. Wow, how interesting does that sound!!!
What I said in my OP is that we can have both skill and coordination. Reducing the amount of buttons required to be good for one does not solve the problem of new players not playing pvp and the only purpose it really serves is to make the game play less interesting and boring. All of the problems you say reducing buttons somehow fixes are outright wrong while creating the issue of people being unable to reach a higher level of play due to straight up restriction of actions.
In the end, if SE actually had better frontline modes and a better reward system for the casuals then the teamwork and coordination that you covet would actually become more common even in a game that is really complex with a lot of actions. If you had 100 times more people engaged in PVP teams would be more balanced, matchmaking would be more fair. In that way you would be creating the situation of more coordination and teamplay by virtue of the number of people playing PVP, not ARTIFICIALLY FORCING IT by making everyone capable of doing the same simple burst/healing/tanking or whatever.
And your little comment about fairness. Is it unfair to be a better player? PVP is not about being fair and making everyone the same. If what you actually mean by fair is by players not getting crushed to to bad matchmaking then that issue is fixed by a healthier PVP population. At that point you would have bronze vs bronze,low gold vs low gold, high diamond vs high diamond etc.
You don't make a game great by severely simplifying it, I am sorry, but that is the truth.