Of course he has an advantage of mobility, but if i do fight him i can paste him. And why would the lord be running around where
BTs can get at him, he'd get killed before doing any harm. He goes with the knights until i need him to kill something scary. Its just fun, one nasty missile to planet kill or back up another unit. No i wouldnt throw him at a fully ranked unit without back up (but sometimes its worth the risk) any more than i would throw the knights in to one. The army works together.
ive been playing these types of gro-pow armies for years, i think i know how to deal with a cannon and some hand gunners.
Characters not really, since their cost includes a chariot and the daemon sword (worth it). The warriors, again no. I cant imagine taking marauders and not spending even more on my magic phase to make up for the lack of hitty and speedy. As for making it faster, not an option for me personally (i dont have the models) but i cant imagine any army that wouldnt be made better by the addition of more knights.
This was just an idea i had, dont think i need help winning games. Even with a bad army.
also,
http://www.dakkadakka.com/dakkaforum/posts/list/0/223865.page#464474