Warptime got faq'd so it isn't very good now, you have to reroll all of the dice, not just the misses or failed wounds, so while it can help with a total fluff, the chances of getting a perils for using it every turn (including your opponents turn) makes it not worth while imo.
I would consider a daemon weapon lord, the tzeentch daemon weapon gets D6 str 4 ap3 shots as well as D6 extra attacks in close combat, so it's essentially doombolt.
On top of that a daemon weapon lord with mark of tzeentch is only 145 points and he's immune to all the anti psyker stuff like hoods and psyk out grenades.
If you want to give him some anti tank, combi melta and melta bombs will make him 160.
For a close combat stat hammer; you'll get about 5.8 attacks average per turn with the lord vs 4 with the option to reroll for the sorcerer.
For terminators, the reaper autocannon is pretty expensive, especially compared to your other options; heavy flamer is a very strong choice, generally taken along with a full rack of combi weapons and a single chainfist per 3 as a general rule of thumb. Especially since it looks like you will deep strike them on one of your thousand sons squads. Personally I find terminators under-perform in general though... for those points and the few you'd save on the lord you could get 2 x 2 obliterators and squash a defiler in there!