Can Anything Significant Really Be Done?

I'm asking this question because I really don't understand the whole waiver/acquisition process after the 7/31 trading deadline. RumBunter says that Nutting should get off his wallet amd make something happen:
http://rumbunter.com/2013/08/19/time...inish-the-job/
It all sounds so Nike-esque easy - just do it. But can it really be done, what with clearing waivers, other teams making claims (sometimes just to block you) and the Pirates now being in the relative MLB stratosphere getting last dibs in most cases? I guess my questions are
Can anything significant be done?
and
What's out there, even if it can?