Question: Can I improve my pokemon sapphire team?

I want to improve my pokemon team and I will take any suggestions.
If you can them please recommend any pokemon that I should add, and thanks in advance.
This is my team:
Swampert lv. 50
Gardevoir lv. 67
Salamence lv. 51
Metagross lv. 55
Latias lv. 42
Kyogre lv. 82