.... I think that BJJ and Aikido (the two biggest of the polar opposites commonly compared in the us vs them realm of the internet) are actually more alike than different. Indeed, given the similarity of root and movements I'm prepared to state that as a point of fact they're actually damn near the same thing .....
I think the best way to investigate this (assuming you're not doing so already) would be to crosstrain in BJJ --- go at least once a week while continuing in Aikido. In a year to two, see how you look at them.