Logic Pro Help user Ploki has made a truly modern looking skin for EXS24.
The original download link: http://www.logicprohelp.com/forum/viewtopic.php?f=1&t=97685&start=380#p583894
Dropbox download link: https://www.dropbox.com/s/rl7wr0kygp6a6ig/exs24_lpx.rar?dl=0
Installation: “It’s a .rar archive. Just unpack and replace LPX.app>Contents>Plugins>exs24.res>Contents>Resources”
As always, remember to back-up first.
Ps. There’s also another ES2 skin, which you can download here: http://soniqa.net/lpxthemes/