You might be happy to know that starting about end of last year, SE has introduced Trust system. It's basically bonding with heroes of Vana'diel and creates their replica to fight besides you. Right now, there's already list of 20+ heroes you can summon up to 3, including the famous Shantoto and even her separate darker persona too.
I did adding sub for a month and using the heroes to help me grind PLD from scratch to lvl 99. Even as of now, SE adds more flexibility for allowing to summon them in some instanced battles too. Haven't tested this yet since I don't have the energy to play more than 1 MMO. ^^;
As added bonus from latest patch, your Adventure companion (if you ever make one) has been recently upgraded and allowed to partake their limit break all the way to level 99 (if you recall, they were previously capped to lvl 75). Now players in XI can make their virtual party in total of 5 players, 6 if you're playing summoning job like Summoner of Beastmaster.
As for F2P, you could expect another Free Login campaign if it happens again. When it hit at december 2013, it was amazing. For like 3 weeks only, I was able to catch up stuff happened on that current Adoulin chapter progress and other things too.