I think it's because of the incredible height advantage the defenders had.
In badlands, attackers had 3 entrances (near cap 3, the building, and through the enemy spawn), only 1 of them gave defenders height advantage.
In Granary, there were 2.5 entrances (defenders had a covered route over everything)
Your map only has 2 entrances, taking either of them would force you to an extreme height disadvantage as both caps are elevated. This is not the case in Granlands.
Perhaps another route is not necessary, but please do something about the sentries. It is very annoying when the majority of the time was entirely focused on how to take out that damn sentry.