I disagree. A good teacher can give you exactly what you need to move on. Thats the whole point of a teacher student relationship.
I see Phi's suggestion that one should "be their own teacher" as a good one, since to me it implies that one should not rely too much on any given teacher and be responsible for one's learning. In other words "own the material" rather than simply emulate or follow someone. A teacher can guide and provide good information, but the bulk of the responsibility for learning has to be held by the student IMO.
In that vein, when it came to aiki-weapons, I reached a point where I stopped and asked what my understanding of aikido and my goals were. The second step was to disregard anything that separated me from those goals, and to look for training (weapons and otherwise) that could help me achieve those goals. I had to make those decisions myself. People are often too quick to drop Sensei names and say do this or that. I would ask, why, how, for what purpose? and if possible try them out and do an objective comparison against certain goals.