1. Those Shaido women are months, if not years from being trained well enough to be used on a battle field.

2. Channeling for hours at a time exhausts people to the point of being useless so the Seanchan would need to have dedicated gateway holders who would take no part in the battles and the army would subsequently be trapped in the new location. In effect creating potential suicide missions.

3. It's sort of like crossing a river on a battle field too... open a Gateway too close and the enemy can feel it ... a crafty general lets about half your force come through then slaughters them.

4. Will require the Seanchan to completely reorganize their military operations completely since they'll have to build specialized wagons/carts, dedicate far more damane resources to opening gateways than they typically would have to a single army group. Look at it from this angle ... there are at least 4 Major Seanchan camps/armies, Almoth Plain, Ebu Dar, Illian border, Murandy border. Each of these would need at least 100 damane to do nothing but open gateways for Traveling. What is that 1/3 of all damane resources dedicated to one task? And odds are this will be the strongest group of damane too.

Sure you could move a pretty significant force with enough preparation, but it raises significant problems. Not to mention if you are facing an AS army on the other side they will have massive linked circles creating 1 big gate way that will take their army about 1/10th the time to move through, without tireing themselves out. Yes you are better off than you were before, but you are still at a significant disadvantage to those who can in fact link.

In the end unlinked Traveling is far more effective for either very small groups of scouts etc