I think allying should be easier. You should get the option after you reach warm I think. It's so easy to make enemies but so hard to make alliances. There should be times when getting an alliance would be easier. One such time is when you are both warring against the same Empire and are at good relations. I shouldn't have to give away all my tech and money to get an alliance with another empire, especially when I am the stronger empire. It makes no sense at all.
Our alliance with the Soviet Union in WW2 was decided because we had a common enemy not because we had some love relationship. It was beneficial to them and us so we allied. This is how alliances work in real life, we both have a common enemy or interest such as mutual high levels of trade. They can also be formed when we need to use each other's territory or pass through as if it was our own. I would like if the game followed this more realistic concept.
I was playing a game on challenging in a small universe. I was trading heavily with the Altarians, nearly 70% of my trade. I also had a strong military. Yet, I never saw my relations go above warm.
I saved and did a test. I gave them all my techs that they didn't have, which was about 10, and then gave them all my money which was about 8000. It went to about Friendly for one turn then went down the next turn... it's really silly at the moment.