other than mobile friendly controls, I don't really see what's different so it raises the question why not just make a mobile client but have it be the same game instead of something seperate...

Well, I know the answer: so they can make F2P microtransaction money in China. Thing is, FFXIV is available there too (though seperate servers and some differences)

At least it seems like they contracted someone more capable than Nexon this time.