Don J. Modesto
In general, I believe that previous MA training helps in new arts more than it hurts.
I'd go with the latter.
My feeling is that the general goals of Roppokai aikijujutsu and Aikido are different. In Aikido, we are generally trying to control their whole body with our whole body (center to center) by establishing a connection (union) in receiving the energy. I found that generally, in Roppokai Aikijujutsu, they are attacking the center of the opponent using small powerful circles. It was their stance that troubled me sometimes because always starting in Shizentai said to me that they weren't necessarily practicing a complete martial science as much as they were practicing a portion of a martial science. I admit my time with them was limited (two years) and that my limited perspective disqualifies me from any real weight on my opinion. I did find that their perspective was very helpful to my aikido but I really don't believe that the average Aikikai shihan uses their principles. My shihan does and I would say Gozo Shioda certainly did but the modern guys don't do anything like what we studied in the Roppokai. I certainly liked their stuff and thought every Aikidoist I knew would love it too.