What may happen, given all the people that've showed up lately, is that Kabuto arrives to see what happened - they surely would have expected Kimimaro to be quicker, and if Kabuto does appear, maybe things'll continue Naruto vs. Sasuke, Kakashi vs. Kimimaro.
Well, if Kabuto DOES show up, it won't be to see what is taking Kimimaro so long. Kabuto and Oro already know that Kimi is dead. That candle in Oro's chambers that they kept watching was symbolic of Kimi's life. Once that candle burnt out, they knew he was dead. If you remember, as soon as it burnt out Oro said something like "What has happened to Kimimaro doesn't concern me, I'm only interested in Sasuke. He can get here by himself."

I would love to see Kakashi vs Kabuto, and to have them both show up on the scene right now would be an ideal situation. However, I feel that if the two of them did fight right now, it would be a very long and epic battle that would drag this arc out another 3-4 months. At this point I would really like to see the current arc wrap up with the conclusion of the Naruto vs Sasuke fight, and move the storyline along. But this entire arc has been full of surprises and I don't think Kishi is done yet.