From the pictures I can't see how crowded the plant is in its current pot. Is the bark mix breaking down? Is the plant growing outside of the pot? You'll notice quickly after you cut the spike the plant will start growing new pseudobulbs that will put out next season's flowers. That's the best time to repot, so the new roots can grow into the new mix.
In terms of dividing, you have plenty of plant to divide. What would you rather have, one big orchid or many little ones? The onc. I have that's similar to yours is really big and put out multiple flower spikes last summer. It was pretty amazing! If you divide you won't get that.