Whether he tells her to or not, there won't be another large battle. Just as Galad realizes that the Whitecloaks fighting each other only hurts the forces of the Light, Rand has realized that any fighting between his forces and the Seanchan also hurt the Light. It fits what the Finns told him and what the prophecies state about the north and east being connected, the west and south, and the two being as one. Plus, Nicola's Foretelling shows that the Seanchan will still be around after the Last Battle.