I believe players should have the agency to conduct diplomacy as they see fit with relation to other empires. This is currently possible with the exception of type of one type of diplomatic request. I think there should be an option to refuse gifts in ES2. This is because while it's kind of nice to recieve free resources in MP, it's not always nice when the gifts involve systems or techs. By recieving techs, you raise the cost of other techs. Hence, you may get bombarded by techs you consider useless, just to drive up your future tech cost. As for systems, I think that you don't get ownership after transfer, meaning you cant evacuate. This could cause havoc on your systems if you are barely balancing happiness.