A smaller-scale battle like CTF would probably need to enforce some job restrictions (similar to what CC has now) to prevent strats that would most definitely ruin the game mode. Like running 8-12 PLDs and being totally unbeatable.

Otherwise, I'm not opposed to Square Enix trying new ideas, especially with PvP. Though personally, after years of playing WoW battlegrounds, I don't necessarily subscribe to the idea that a 1v1 mode would be any better than 1v1v1; the former comes with its own issues, like players giving up after the first engagement, or getting team diffed so hard you spend the entire game getting camped at the graveyard with zero chance to recover. Still though, I'd be curious to see how some of WoW's battlegrounds translate to FFXIV.