Agree with soomemafia, remove lemartes and captain and add reclusiarch with jump pack
remove tactical and put on assault; discount on razorback and rhino make them more viable if you aim at a fast light mech, or keep them on jump pack/drop pod them for a fast assault
personally i don't like
DC 'cause are too much expensive and you need to bring them close combat very quickly or are a waste of point; against most of the enemy, assault marine with a sanguinary priest are pretty similar use with lower point cost. However, don't
DoA them: deploy them behind a huge cover and make them jump+run toward enemy. If you're a bit lucky you can assault on turn 2
Or put them on a
LR to shield them until charge range.
someone use
DC with bolter into a pod, to deploy them behind enemy lines, shoot the hell from bolter rapid fire, and then charge on the next turn; they are relentless so you can shoot 2x shot AND charge and that's better than +1
CC attack in my opinion (
DC normally get 2A so not a waste of attack equipping them with bolter)
Fragioso is a little cheaper than
DC dreadnaught, take a look on him (however,
DC it's way too cool to be totally wasted

)