I like how Chaos players are dropping one of our codex's most significant advantages over other codex's simply because ppl call cheese and dont like it. well, we do the same to SW codex yet i dont see them dropping their JoTWW Rune priests and ML long fang spams and other absurdly powered builds. We chaos always get the bad side of things. 
but back to topic, Mephiston can be dealt with easily with a muiltitude of counters such as plasma guns, power weapons, Daemon prince, Kharn, Anything with a high strength and low ap such as 1 or 2 like Melta or Lascannon or plasma. Dreads do very well against him too.
To fight Orks- get lots of chosen with flamers and regular marine squads or Khorne berserkers who excel at dealing with hordes with the amount of high strength and plenty of attacks they have plus their space marine saves. ( note: good job on giving berserkers a champ with Powerfist but you may want to give their rhino daemonic possession instead of extra armor) Noise marines do very well also if you give them Sonic blasters cause Sonic blasters count as assault 2 which means u can constantly keep moving away while firing full range and both shots. watch as those orks get mowed down without getting anywhere near your guys. thousand sons are pointless against assault heavy armies and for their points are not good to get dragged into a prolonged melee fight. (plus the sorc is very expensive for a single model)
also dont underestimate the raptors. they are very good at tank hunting with their two melta guns and 12 inch moves. they can easily get in range to get those pesky transports or tanks rear armor.
Also no need for Icon of Chaos Glory since your guy's use the champs Ld which is 10 so it will hardly fail. and you dont waste points that can be put elsewhere.
but back to topic, Mephiston can be dealt with easily with a muiltitude of counters such as plasma guns, power weapons, Daemon prince, Kharn, Anything with a high strength and low ap such as 1 or 2 like Melta or Lascannon or plasma. Dreads do very well against him too.
To fight Orks- get lots of chosen with flamers and regular marine squads or Khorne berserkers who excel at dealing with hordes with the amount of high strength and plenty of attacks they have plus their space marine saves. ( note: good job on giving berserkers a champ with Powerfist but you may want to give their rhino daemonic possession instead of extra armor) Noise marines do very well also if you give them Sonic blasters cause Sonic blasters count as assault 2 which means u can constantly keep moving away while firing full range and both shots. watch as those orks get mowed down without getting anywhere near your guys.
thousand sons are pointless against assault heavy armies and for their points are not good to get dragged into a prolonged melee fight. (plus the sorc is very expensive for a single model) also dont underestimate the raptors. they are very good at tank hunting with their two melta guns and 12 inch moves. they can easily get in range to get those pesky transports or tanks rear armor.
Also no need for Icon of Chaos Glory since your guy's use the champs Ld which is 10 so it will hardly fail. and you dont waste points that can be put elsewhere.
