And do lv 25 agents spam worth it?
Well they are if there is not drawback to them being killed. A list of uses for Ash Slaves:
-Tie up more powerful units, to which they would have to at least waste AP trying to escape or better waste on trying to kill the little snots.
-Intercept Ranged Attacks and block Line of Charge.
-Gains you extra activations so you can hold back your more powerful units until enemy units have wasted their AP.
-Chip away on units with lots of LP or finish off those that barely survived before. Also extra attacks that will have to be dodged or suffer at least some little damage that will add up.
-Azur Agents can be stealth hunters or one shot bullets.
-Church Agents super cheap healer & buffer.
-Empire Agents cheap tank or beatstick.
-Samael Agents flying speed bump or buffer/debuffer.
-Wiss Agents spam attacker or cheap ranged attacker.
All this and they don't trigger Death effects or award VP or trigger Shock when killed. With Genma pumping bind points into the Djinn so it never goes away. Yeah those Ash Slaves are pretty damn worth it and only slightly more balanced then the Djinn's Absolute Copy ability which is pure cheese in its present form.
As for cheap prowlers they work in a few ways too. Stealth and Infiltration hunters, support killers, and AP deterrents. Azur has super cheap units that can be hidden is fine for offing a wounded unit or take down most low to mid-level units which usually cost more anyways. And with a Harod or Freya or Kyler hanging around your enemy units have to hold back some AP to Dodge or Seek meaning they have less to do for their other actions. Plus to a lesser degree then Ash Slaves those cheap prowlers give you an activation edge that can be used to wait for your opponent to open up or exhaust AP. I'm willing to lose Harod if it means I take down Lilian or Rayne instead. Yeah they suck against heavy tanks or some of the higher cost units but thats why you pick your targets. Plus the new unit Wolfgang and Gnosis equipment card should make for great boost to cheap prowler uses.