This discussion almost a year ago centred around how to build a maelstrom assassin:
I linked to page 3 because he posts a quick starter build there, but the whole discussion is well worth reading IMHO.
Maelstrom sin was aerial's choice of character the season after he beat the entire game on a barb using TUs only (see his thread in the Guides forum "TL;DR 2H barb" showing videos of all of it). Many people still use that as a quick-reference checklist for ubers, since it's a condensed list and shows a video of all of them. Thread here:
All in all you may be right in what you say and I'm happy to acknowldege that I'm no expert, all I will say is that anyone considering playing maelstrom sin should listen carefully to what someone like aerial has already said on this subject - as you can see reading through the first thread above, a lot of his knowledge has been tried by switching builds often at high levels to see what actually works as well as theorycrafting.