I can't put into words how much I don't like this.
The trailer feels exactly like what I excepted from its mobile game iteration: flashy, sparkly, casual fun without much substance. Nothing of the things that define FF14 and ARR. Not even a mention of that weighty, epic story, no scenes with a serious or darker tone. Just a firework of fun colours and happy partytime.
(Also, I know we didn't have au ra, viera and hroth NPCs in ARR but I don't think it's a smart move to not include them as playable races from the start. (At least I didn't see any in the trailer?) They are such fan favourites after all, esp. viera and au ra. Not being able to play as either of them and potentially having to wait till heavensward/shadowbringers, which is years from now, makes me even less interested.)
Also, since mobile gaming is a lot more widespread in Japan and China iirc (though please correct me if I'm wrong) and gacha makes so much money, in conjunction with their restrictive and outdated spaghetti code for PC/consoles, I'm worried that they might prepare to slowly move away from PC/consoles alltogether and aim to turn FF14 into a purely mobile title in the long run. Not next year or the 2-3 years afterwards but perhaps across the next 10 years with the full switch coming when this post-EW arc with its 2-3 expansions comes to a close.
I guess like this they can start over with fresh code while also turning it into an even more "profitable" (but not necessarily more player-friendly) game.
Though I guess with new code/a new engine they could also pull a Genshin and try to develop a true cross-platform game that works on mobile and stationary devices. (Though this might make cross-platform team-fights hard/impossible because of the stark differences in gameplay limitations between platforms. Genshin is already held back by that a lot and it shows.)