Re: Things to look for in a teacher
I don't see why any of these things would be difficult for a beginner to judge. The main things that Adrain is saying are important is that the teacher should be hands-on and have a systematic method of teaching. Obviously the part about having a "high level of skill" is relative, but even beginners should be able decide if someone can move in way that looks and feels impressive to them. On that point I would add that it's always good to see and feel a lot of different people and arts to get a sense of what else is out there and how good a given teacher is relative to other alternatives.
What I see from a lot of aikido teachers, including some of the most well-known names, is a very hands-off teaching style where only a select group of carefully trained students will ever touch the teacher. These teachers want to ensure that they will always get a certain kind of ukemi that is designed to make them look good so that they can cultivate an air of great martial skill that might not be grounded in reality. This is particularly true of seminars, where people are expected to pay $100+ to attend while most of them will not even get to work directly with the teacher at all during the seminar. For that kind of money, I think every participant should at least get to touch hands with the teacher once.
A lot of teachers also take a very non-systematic approach to teaching, believing for various reasons that students should figure things out on their own with little or no explicit instruction. This approach might have worked in traditional Eastern cultures where there were few other options, but in today's modern Western(ized) world we have access to so much more information and skilled teachers in various arts that those who do not take maximum advantage of this knowledge base will be left behind by those who do. I think this is already happening in aikido right now.