With due respect to Rhys's run, and I have truly enjoyed running it from time to time, and hope to do so again.....there is a difference between clearing to Prince in one night, no matter how long it takes (4+ hrs?), and running a prince run in a little over 2 hrs. Rhys runs are very enjoyable, with good companionship and lots of laughs, and perfect for that mindset.
The second type take a bit more focus, no afk's, starting on time, loot handled while chain pulls continue etc. This takes a different mindset, and sometimes a bit higher level gear and assumes everyone is very experienced.
Some people can flow between the two, others cannot. I enjoy both at different times, where some see the second as too structured and intense, and the first as too loose and chaotic. To each his own, but this is why there are different types of runs.
It is also true that the group MikeR and I ran was the initial Kara group for TF. It seems each time we could really defeat the instance, something happened (change of personnel) which threw us back and cause a rebuilding effort. Many of the other Kara runs include people which learned and benefited from our mistakes and many wipes on various bosses. We have never really enjoyed a few weeks of easy clears to actually 'pay back' the investment we all put into this, in the form of badges and actually coming out of Kara to the good gold wise. I think it would be fun with a focused team to do a bit of this. Actually, doing this for a few weeks before we approach ZA would be a good chance to solidify the core team for a new challenge, and also see some of the bosses we rarely saw.
As to ZA, I only want to do it if we are going to hit it with the expectation of doing very well there, and with a focused group. This is exactly the situation where I do best in the second mindset listed above. I would fully expect to wipe, but have a goal of progressing to at least one new boss each week, and work on getting the time down to get those additional rewards.