About those vector icons
Long but good article.Glad he got into (and linked to the excellent article about) font hinting, because that is of course the solution.  A simple vector format is not enough, you need to define what parts should scale how, which are rigid, which are elastic.I don't think higher resolution displays actually help, because the real limitation becomes the human eye.  Though the new display could use the 'old' normal sized icons as small ones, your eye couldn't distinguish some of the details that worked before.Anyways, it is an interesting problem and one that I don't envy designers for.