well i'm not sure if you were going for this, but your composition is almost perfect. lots of troops, lots of variety, not an excess of heavy weaponry.
if you wanted a bit more bang for your buck, i would advise making your chaos marine squads 10-man, remove the lascannons, and mount them in cheap rhinos. you would be able to play them as 'hit squads' and use either 2 flamers or 2 meltas in each squad.
also, it might be worth noting that the mark of slaanesh is nowhere near as efficient as the the other marks, especially when it comes to making your terminators more effective.
if you wanted a bit more bang for your buck, i would advise making your chaos marine squads 10-man, remove the lascannons, and mount them in cheap rhinos. you would be able to play them as 'hit squads' and use either 2 flamers or 2 meltas in each squad.
also, it might be worth noting that the mark of slaanesh is nowhere near as efficient as the the other marks, especially when it comes to making your terminators more effective.