Moving to Elite/Ultimate, how to prepare

I am about to finish 2nd expansion. All my resists are capped except Physical but that is only on veteran, I will have to find more when I move to a higher difficulty. I have heard a lot of people go straight to Ultimate, that definitely appeals to me as I would like to get to end game stuff and start a new toon as well. Is there any reason not to skip Elite difficulty?

Is there any rep vendor stuff I should acquire before starting new difficulty or can I drop back down at any time to grab something? Is there anything else I should do before increasing difficulty? I am level 75 Spellbinder using Aether damage AAR. I have have 1800ish Aether damage and sources of resist reduce but not much really in the way of damage conversion yet.