I'm worried about summoning the prince and thirster. They have to come from a non daemon character and drop within 6" and scatter. seems like mishaps will happen a bunch also if your characters are in the middle of a blob you might not be able to drop them in at all since summoning happens before movement. I have to play test this.
I just noticed yesterday that it says no models with the daemon rule can ascend. so no possessed or warp talons. maybe a 3 man bike squad could be a good delivery method. have them find a safe spot for a possession the next turn
Heck, even if/when they do a FAQ to make it so the character has to die in a challenge, that's not that hard. I threw my guys at an opposing army and got into combat and just challenged like crazy. I kill my opponent's character or I get killed, either way I'm getting a Blood Tithe point. Had plenty of them piling up once the army seriously started getting stuck in.
My opponent did catch on with the destroying units thing, though. Shot up all of a Bloodletter unit except the last guy, who he left alone to deny me a point. Poor guy wasn't able to get into combat before the end of the game, either (I kept killing the stuff close to him), so he couldn't do a challenge and possibly net me two points getting killed (it was the champion).
You'll be racking in a lot more points while it isn't fixed, though. Your units don't even have to come close to melee, as long as they get wiped, the character goes down with them for an extra point, even if it was some sneaky tau git you would never have reached for assault.