To support mains, is magical footwear better or zombie ward better?

zombie wards usually take priority but if you were an ap supp or enchanter you can have both without sacrificing much

You want Magical Footwear. Footwear spares like 650 gold on boots expenses + you'll already have a Sightstone. Unless you're going Inspiration + Domination (which I don't think a support would or should do), you should take Magical Footwear between the two.

future market master race.

It depends on if there's another specific rune you want to go with it, since I would like either one. So really it comes down to if you want domination as your secondary, or inspiration.

Zombie Ward is amazing, assuming that you actually use the vision provided. If you never look at your mini map, then extra vision won't help cause you won't use it.

Magical footwear is good, especially on slower champions, but it depends.

Also think about what else you would choose with these runes. Like, I take active item CDR when I go into the domination tree, so then I have Locket, Redemption, Frost Queens/Targons, and Sweeper on like a 30 second cooldown at max stacks on enchanters.

I am a fan of free ass boots (and cosmic insight). (I also play janna who gets bonus damage from her MS anyway though.)

Zombie ward is pretty sexy, but I'm not super drawn to the other dom tree things most of the time. Lots of active cdr is ok, but if I'm not filling my inventory with mostly item actives (which is certainly reasonable on some supports) I feel like I'm being wasteful, plus I'm unlikely to get more than a handful of bounty stacks until mid-late when teamfights are going on, and I'd rather something with more potential early impact.

(I certainly appreciate non-supports who take zombie ward over eyeball collection though.)