Currently the biggest problem with grind spots is finding one.  Since there is a 15 minute CD people are less willing to swap when looking for a grind spot, this causes conflict.

I suggest that if a player has not bought a trade item, used an imperial trade merchant for, and not killed a single mob/player in the last 15 minutes they should be able to swap as many times as they want to a new channel, however if these criteria have not been met they should be met with a Channel CD timer first swap of 15 minutes as long as they do not break any of the criteria on the new channel they will be free to swap until they kill something or use a trade merchant.  IE, you are grinding and someone duels you for spot, you lose so you swap, the channel you swap to has someone at the grind spot, you should be free to swap again unless you kill something/buy a trade item/use an imperial trader.  You should not get penalized for chosing the channel you swap to poorly.  

There also should be no timer for swapping to Arsha even if the previous criteria has not been met, only away from Arsha if the previous criteria has been met.

This is a good idea, but need to think carefully about any exploits it might open up. I can't think of any besides the one you already mentioned.