This has been reported several times online now. It sucks. I have not pre-ordered because of this and now will not be buying the game at all - and I'm a Battlefield enthusiast with mouse mats and posters and all that jazz.
My clan/platoon will not be moving forward and buying Battlefield 1 without me nagging them to or getting it for them all as birthday presents - and that's quite a few day one sales of the game and premium that'll now not happen at all.
We won't believe any * like "Oh, we'll do it later, no really" because the same was said for Battlefront and that never had decent joystick support provided either.
Our only options are third party tools that inject DLLs to convert joystick input to controller input but come on, that kinda stuff can lead to getting false-flagged and banned. ☹️
Fortunately, it's not like there aren't other games to play. Lots of great ones on sale, with free maps and all too.
It's a shame though. We were looking forward to this game and to have features starved out like this... just, no.