Yeah the dp is somewhat out of whack. He's pretty good, depsite costing what he costs. For this discussion, assume the DP is spawned from a near dead chaos lord for max efficiency.
If you watch the dp fight, it becomes clear to you that his disruption is incredible. I've seen special attacks of AOE 15 in approximation. Literally whole hordes of armies go flying in the air. Insane. It particularly bothers me in chaos mirrors when the DP is all the opponent has left and yet possessed+oblits+csms+the kitchen sink still can't kill him cause of his disruption. He's pretty close to being what he should be, but just needs some minor tweaks to finish the job.
1)lower the firing rate on dps special attacks except for one special one which is just right (the one where he breathes like fire into his hand than swings it in a circle. that one has just the rate aoe and timing)
2)lower HP by 1000. restore the 1000 hp with daemon strength upgrade (meaning even if he's at 1 hp when the upgrade is done, 1000+hp is added to both current and max HP).
Or possibly change armor to commander and give 3500 HP. This however would make the dp a fairly good monster high/vehicle high counter and currently he is not.
3)shorten daemon strength upgrade by 20 seconds. Currently is 80 secs tieing it for first on the longest non hq/tier upgrade*, falling behind those by anywhere to 10-20 seconds. but is an ability that affects just one unit. 80 secs is really really long. Not to mention its jammed in a building that has several more prevalent upgrades before it and only affects one unit. 60 seconds makes more sense.
anyway, the suggestions are reasonable and merely tweak him rather than rewrite the whole vid game engine. though I'm sure this will get out of hand very quickly with people asking to shrink him to a midgets size and some asking to give him a and iron man type uber proton cannon.
but the problem is clear. if the dp used his sword more often than he used his special attacks, he's be ok, but his special attacks keep things from fighting back which is where you run into real trouble. Its the special attacks that say, keep your ogryns and your FC and your possessed from being able to fight him straight up. I say this because I've killed many a greater knarloc with my chaos lord and my sorcerer alone simply because the knarloc seems to lack any real disruptive special attacks and so my chaos lord and sorcerer can easily trade blows and bring it down to size. Thats the logic. Make the DP more of a lesser knarloc essentially.
*can you guess what the other one is?