Quoting Twilight_Storm, reply 10 That would be a bit OP, costing no fleet. I'd say 6 is a good number for them though, or make it equal to each faction's colony frigate. The rate they improve diplomatic relation is fine as far as I'm concerned though.
Why would it be? You still have to do the research costs, build the envoy ships and more than likely invest in your envoy abilities to get anything but the most basic pacts. And since pacts are an indirect bonus, they will have to be quite good for players to invest time in it versus something that will directly help them kill another player. When you're fighting for your life, fleet supply is too precious to waste on pacts.
Sorry, Goa, I missed this when I posted my last comment.
The reason I think it would be OP is that despite the fact that Envoys have no combat purpose, they do provide vision of each world the person you send it to owns. In normal games, just because a person allies with you doesn't mean they want you to be able to see everything they're doing. That's why Planet Vision is optional.
Yes, I do know that most online games seem to be set teams, but the people who want other types of games like a FFA shouldn't be resticted by that fact and be forced to spend resources on envoys just to have the same advantage. I would however be in favor of cutting them down a little more, however, to the cost of a colony frigate, as to me, they seem to be just about as useful. They should cost something in supply, and it's not like you have to build them in mass numbers. To me, they're meant to come out somewhere between the 3rd or 4th supply upgrade, where a couple of these don't make a massive dent in your supply.