Very interesting post! Yes, I personally have seen this type of training environment, and have seen extremely talented aikidoka come out of such a dojo. I do think it becomes a personal choice on what is more important; the "edge" of this type of situation, or the feeling of general well being from the other.
Do you think though, that it might be well possible to become a talented aikidoist without this type of environment? I certainly do, and think it just depends on the individual and what works best for them. Some people thrive on this type of competition, while others it makes miserable. There is nothing saying that you won't be able to find an equally good quality dojo without the politicing (for isn't that what it really comes down to) you find at that dojo. Also, is it possible that the "generous" dojo you started practicing at in the first place has moved on a bit from a technical standpoint? Organics come into play, and not only do people and their aikido change, but also whole dojos can have a radical shift in the dojo culture over time.