After playing a lot of the beta, ive had a a lot of trouble trying to play with any kind of diplomacy, unless they are both the same race and faction as me. I think it stems from the new faction relations modifier. It seems way too high and kind of makes diplomacy useless. Plus there is no research letting you bypass it. I understand that tec rebs should have a big modifier against any alien (due to thier xenophobia), but -10?! its a little extreme and impossible to overcome, even if your attacking thier enemy and doing thier missions. And loyalist should have very little impediment to making peace with reb advent or vasari, since both have shown a willingness for peace. I think the faction relations modifier should be toned way down and add a high level tech that can overcome it. like if your advent rebels, tec rebs should be -5 and loyalist -2. Otherwise you have hamstrung anyone who uses diplo in thier stratagies