Oh i also had that problem for a time. I used A* in decision process for a short time ; after that it was all about "if isolated" and count territories while checking isolation etc.
And in that time , I used a tie-breaker for that. With a little tie-breaker which i cant exactly remember right now ; it always preferred the squares closer to opponent ( actually , not the closer ones. More like ; it'll choose the square closer to , direct line between me and opponent ). Really hard to describe ; so lemme just find it..... ugh can't find it , my coding folders are total mess

x1 = current_square.x - opponent.x
y1 = current_square.y - opponent.y
x2 = my.x - opponent.x
y2 = my.y - opponent.y
h = h+ (x1*y2 - x2*y1) *0.001 // kk i thought i would be easier to understand like this but doesn't seem so now eh?
This is kinda , "best of both worlds". It'll move diagonally in maps like "empty-room" or "huge-room" but it'll also prefer "NNNNWWWW" like movement (any word to describe this? ) in maps like "joust".
Still i don't think A* is a crucial part of anybodies bot so it's just a little enhancement.