A lot of the movements of the large frame didn't make much sense to me until I got a guandao in hand. Arthur Rosenfeld talked about how guandao was the primary "weapon of skill" in taiji on a podcast and I had to experiment myself.
I will eventually learn the kwan dao. My school has a set curriculum of when you learn which weapon. Of course, it's going to be quite the challenge for me because it's supposed to be a heavy weapon and a very long form that really tests and builds your strength. Not necessarily looking forward to it!