Two things that skype for Linux needs is

1) single instance switch (prevent launching duplicate instances if you
accidently click on the icon again, and also needed for #2 below

2) command line argument so that you can use callto: links (and of
course redirect that to the running copy (if any) rather than start
a new copy.

Of course there are a lot of other needed items, but these two are needed
just to get up to windows functionality.