There's a lot more to it than this.
A lot depends on the terrain, in my experience (I have multiple modern 2 and 4 strokes) small bore 2 strokes really struggle on slower, rocky hills where traction is difficult and you can't carry good speed.
Up smoother tight hills, even slippery ones, small bores are awesome!
Big bore 2 strokes are great up any hill, unless you have to be very sensitive with the throttle.
Generally speaking though if the hills tough, I think a 4 strokes a bit easier to get up on, however the difference is less than it used to be, as modern 4 strokes don't like to lug much.