Thats A Great Team, But It Could Do With A Nice Staller instead of all sweepers. I Would Use Blastoise, But Its Up To You, Maybe Replace Starmie, its the weakest on your team, in my opinion. But Thats Just I Would do. If You Want All Sweepers, Thats Still A Great Team. Another Option Might Be To Add A Super Fast Pokemon, As Most Of The Pokemon On This Team, Are Slow. But I Guess Thats Why You Have Starmie, Anyway, Great Team!!
Hope This Helps:)
P. S. My Platinum Is Going Great, My Torterras Now A lvl 54, and I Got Through Victory Road!:)