Oh yes, I would totally love it if I had a girlfriend and if she would wear that kind of outfit, though I much prefer leather leggings than leather pants. These outfits really exude a sense of boldness and I find that very attractive! And I wouldn't mind other men checking her out, I think that it would be a good sign. As a man passionate about female fashion, I would love it if my future girlfriend would have the confidence to wear the kind of clothes like leather/shiny leggings, it would be a huge turn on for me :).
The leather is not really my thing, though I am sure some guys would love that. Personally, I would like my girl to dress up even more. Why would I want her to dress like crap because other guys might look at her?