I think the SW1 is honestly the best out of every one of Mikatagahara themes. IMO, the only other theme that can really stand up to it is the SW4/SW5 Tokugawa versions
SW2 Best cuz you can feel the chaotic situation more clearly. Be it takeda's pursuing, tokugawa's escape or kotaro's intervention, this theme capture everything at once.
I like SW2's theme (and stage) the best here. SW1's is pretty good too but SW3 onward remixes aren't great. Shingen's SW5 design is definitely my favourite though :)