if aliens are paying any attention they should be able to stop a move
That's a big if. When you have players who haven't only just found the game and will stop playing it a day later, then they might be more clever than your average player. I get the impression those who like this system are too used to public games filled with inexperienced players, and have no idea how much fun a game full of experienced players- with high levels of coordination -can be. In such games with the old system, whether or not you get all your bp for the new base position is based on how well your team coordinated the move and how well the enemy keeps you from deconning those last structures. With the new system, a failing base could start disappearing without any alien realising why until it's too late.
*Mr. Goon looks at the base he's attacking* "Oh good!" he says "my teammates have taken down those turrets!"
*Mr.Builder- who was the one who removed the old base turrets while on the other side of the map -has got 2 nodes and a turret up during the attack*
*Mr. Goon steps onto the last node* "Muhahaha!" he cackles "I've got the last spawn!" He decides to destroy it and win the game. Unfortunately it disappears from under his feet. "What the hell?!" he exclaims.
*Mr.Builder has finished the new base and while the rest of his teams sets off to attack the alien base, he sets off to the next place he'll move the base to in the event of a base attack*
A well coordinated team could take advantage of it so much that it would be a great head-ache to finish off any base without it popping up somewhere else.