Here is the list of problems with poison pool:
1. Unlike desecrate, it lasts a long time
2. Unlike desecrate, it has a much bigger are of effect
3. Unlike desecrate, you can't tell how many you are standing on
4. Unlike desecrate, minions from a yellow pack can have this ability. It is especially bad if it is a hoard. Because it sits on the ground for a very long time, many will stack and you have no idea how many you are standing on
The problem is you're crying and moaning about something that shouldn't be changed, move on.