Ok - with some apologies, I was confusing the DP with the Greater Daemon.
However, the DP is both too cheap at +50 points and somewhat overpowered:-
- 3+ Reinforced Armour, Invulnerable save and Fearless makes him virtually impossible to kill (around 1/14).
- 2x extra MW (TK) attacks in Close Combat Plus 1x extra MW (TK) attack when firefighting makes this a very potent unit.
- Teleport allows him to arrive with a very focussed assault.
- Finally allowing it to avoid being the Supreme commander means that ultimately he is also expendable - allowing the Chaos player maximum freedom to deploy this horror with no consequential drawbacks if it is lost through the opponents skill or luck.
The Greater Daemons are even worse in some respects!
- Under the published rules, at 100 points for a DC3 or DC4 RA Titan and +50 points to keep him, the only problem is the risk that it will not appear when wanted. 8+ will appear 15/36 on 2D6 times, or around 42% of the time. So it is more probable that it will appear than staying off-table
- Some Greater Daemons are evidently better than the others - IMO the Tzeench Daemon with 30cms move with a strong Firefight attack is the best, even though it is "only" a DC3+. I suspect that one of the main reasons you do not see more of these beasts is actually the "hated" factions rule because people seem to prefer the lesser deamons of another group.