You can no longer spam elite units. Recruitment is tied to local social classes (Nobles, Warriors, Plebs, and Foreigners). If you lose too many nobles in a disastrous battle, you might find yourself unable to field heavy cavalry for years.
In battle, use Ctrl + G to create formation groups. This ensures your line stays cohesive when you issue move orders, preventing the AI from exploiting gaps in your ranks. Total.War.Rome.II.Imperium.Divided.MULTi9.part4...
You can find the latest patch notes and updates on the Total War Official Blog to ensure your game is optimized for the best performance. You can no longer spam elite units