Nothing wrong with being an otomo - good practice, it sharpens the mind. Although it is a much easier task nowadays then in the training days of O Sensei.
Very good practice! I never served as much of an otomo, but what little experience I had in a similar capacity was very good for sharpening my attention...I remember surprising my friends a few times with my ability to read their intentions (little things like wanting an item off a shelf or what have you) so quickly they looked at me like I had just read their mind (I simply observed their body language and responded right away). The uchi deshi at our school (usually only one active at a time) have a more intensive experience than I ever did...particularly around New Years, which lasts about 3 days or so. I've often thought how I'd like to experience that, but also at the same time how pleasant it is not to have to always be quite so "on." I think awareness like this is usually more important than proficient technique...not that technical ability isn't also very important, just that I think the ability to read intention/body language is generally more applicable to day to day life.