Yes, but back in the days if you couldn't march halfway across the continent to support an ally, there was no point in having distant allies. You can support an ally with an enemy close to them by taking a triangle of the theoretical centre points of realms and creating a penalty equivalent to the square of the direct distance less the sum of squares of the other sides. Thus any triangle formed where your direct distance is longest and you aren't immediately adjacent to your ally (forming a right angle triangle) you will be penalized far less for having an ally close to the enemy. Other sets of circumstances can use more standard formulas to derive a penalty.
We can return to an old penalty but use new game features to make it more intuitive and scalable. I recall us moving to a coordinate system for the regions - this enables us to use realm geometry to logically apply penalties in ways the players can control. Very long thin realm? Extreme ends have extreme penalties. Capital isn't near the geographic centre? Far end has amplified control penalties. Instead of applying top down measures we should look to structure the environment, imo.
The way this can be applied to alliance blocks is in the region control penalties. Central region of the alliance? Great! You will have great realm control because bandits can't escape to unfriendly regions. Very large alliance and it's a peripheral region? Well now you have the undesirables of 5 realms congregating in the rim - it becomes much harder to control such a region.
