I believe that leather is a conundrum, because there are so many faux leather products out there, and no one really knows whether or not it is real. Would a vegan wearing faux leather be just as bad of a message as a vegan wearing real leather? A vegan could lie and say their real leather is fake and a vegan wearing fake leather might be labeled a hypocrite for wearing "leather". Unless the fake leather vegan has a bright red sticker claiming that it's fake, passers by will assume it's real or just not really care.
Honestly, it is much worse to claim to be a vegan and buy leather products that you don't need, such as designer bags and such. Leather shoes are a gray area because there are also animal glues used in many non leather shoes. Also, a lot of vegan shoes are very expensive, or uncomfortable or just look ugly or plain cheap. I hate to say it, but if you are working in the professional world, your superiors judge you based on your quality of clothing. I would keep my expensive shoes.
Also, it becomes harder when you work in construction or industrial design because a lot of safety requirements involve leather gloves, steel toe leather work boots etc. I think we also forget that many plastics contain animal ingredients, so we are all kind of screwed in the shoe department. Also, polyester, rubber, plastic and many synthetic materials do not breathe or stretch with use and if you have a sensitivity to latex, you are also screwed.
All in all, one or two pairs of leather shoes is not as bad as eating meat everyday.