Actually, I meant it should not have been made obsolete. Travelling is an extremely powerful tool, the areas you can use it are only limited by your imagination. It had only one flaw, which was you needed to spend some time in the area to use it. I'd rather have something this powerful had a downside.

Skimming and Travelling should require roughly the same amount of OP. We've been told only the opening of a gateway has to do with strength in One Power in the books (I think it's in Rand's POV when he Skims with Aiel to Caemlyn). Well, a gateway is a gateway whether used for Travelling or Skimming. Plus, no character has ever said "I'm not strong enough for Travelling but I can Skim".

 

I just want to clarify that my reasoning that Asmo didn't Travel because of fear of Rand sensing it had more to do with Skimming only needing one weave, versus Traveling requiring two. Rand might miss a single blip on the radar, so to speak, but he definitely wouldn't miss two. The first might be confused with some sort of echo or other after affects of his causing the rain (remember that here Rand is untrained and maybe Asmo is counting on that). Two strong weaves would be sure to catch his notice. So, he saw the benefit of a single weave to Skim outweigh the cost in time (a mere couple of minutes).

 

Anyway, as has been said, it is more likely RJ just hadn't fully thought out Traveling and Skimming. The above is merely a way to suspend disbelief and provide a semi-plausible explaination for Asmo's behavior.