It's mostly that in Capcom's you can combine moves more dynamically and in fun ways rather than do the musou standard of normal > special 1, normal normal > special 2, normal normal normal > special 3, normal normal normal normal normal normal normal normal > special 8, etc.
They both could stand to make duels and bosses more fun, with lock on etc. too. Some of the musou spin offs like Hyrule seem to have great improvements over the base stuff, others like Berserk not so much and yet more are failed experiments (whichever was that gave you armies).