I enjoyed it a lot on the first level and halfway through the 2nd level. Then I found out they get rather impossible to solve in 3 tries. I was shocked to find out that every try the resources are taken, that is just outrageous!! When I fight I don't loose units that didn't die either, why should my goods be taken when they weren't the requested one?
Also, when fighting and I don't make it I have options to better myself. I can research better units or get/level up GB. There is no such option for negotiations. You are allowed to go to almost the end of level 2 and then you have to quit or pay up. Totally not comparable to fighting which you can end without paying.
So please announce the GB that will supply extra tries for free and do not make it high age. How about we ditch the Colosseum and replace it with something to make negotiations playable.
@jaelis: have you even tried negotiation on higher levels? It sure doesn't sound like it, all your comments apply to level 1 but not above anymore.