I really don't like space empires. I tried SE 4, got it on steam for £4, and its a wonderful game full of really neat ideas. The only problem was the interface was naff, the game always seemed too complicated* and in the end I just stopped trying to learn it. Any gems it did hold were quiet obviously locked away from plebes like me.

As for diplomacy I realy don't remeber a great deal about it. Sure there were differnt types of aliances but the AI seem to change ther opinion of me in seconds and without any logical explonation. Hell in one game I bombed an empire to dust without declaring war (and without them declaring war on me?!) In my opinion TBS games should be as open and as explainatory on the rules as possible. I want to know why they declared war, and although not relating to diplomacy, I want it to explain exactly how range works and what happens when it runs out, how combat formulas are worked out. I play tabletop games and I enjoy knowing the rules and risks involved with all actions and I don't know why games don't let you see under the hood.

Anyway back to topic perhaps you could explain what was so good about SE diplomacy? 

I personally like the bare bones approach of Gal civ2 and Civ 4. With these games you can trade and pay for comodities in multiply ways. Tech, tech +cash, cash+ planet, ect. Though ultimately it did lack the more realisitic kind of interplay of stateship. On the other hand EU:Rome VV (the only EU game I have played) had the more realistic system of treaties but ultimately wasn't quiet as assessible as Civs system. I personally would prefers a hybrid system where trading was done on one of those large "trade tables" but with additional treaties conditions like garanteein inderpendance (sp?), demanding tribute, forming trade allances ect. Which I ultimately would prefer as it allows the simplisity of  the first system with the depth of the second.

* Complexity itself isn't the issue, the issue is that it didn't explain the rules. I'm prepared to put up with the bad interface of EU:R because it explains the rules to me. I hold the mouse over anything and it tells me what it does and what it means. I'm prepared to put up with the HORRENDOUS interface of Dwarf fortress because it has plenty of online referance materials. But SE4 had neither and ultimately left me feeling like a Gaul staring upon the gates of Rome, full of so many wonders that I would never understand. I will attempt to play SE4 again later as it was very promising and everybody says it is soo good. I'm sure even this barbarian can be civilized.

Unfortunatly no. Steam just supplied the game with its rather useless manual. The espionage system does sound rather intresting and is certainly something I would like to see in Elemental. I also like the idea of tributaries and the ganging up behavour sounds awfully similar to a mechanic in Gal civ 2. 

As for allies  providing bonus, that sound like a good mechanic and could certainly help deter the all to common conquest based steamroller effect. And make other less militaristic victory conditions more viable.

As for SE4 any chance you could post the links to these modding guides?

From what I recall, almost all the data for SE4 was stored in plain-text files. I modded the game a good bit myself to suit my tastes, and it all seemed pretty self-explanatory at the time. I don't think I ever bothered going looking for guides. Mat - depending on what you're trying to do, you'll probably be just fine if you just go and start poking around the data files.

I liked SE4 and SE5 a lot; it was always only the somewhat crap AI that stopped me from playing. However, I always thought the diplomacy and espionage were weak points of the game, and probably not things Elemental should try to emulate. The EU series is probably a better place to look for diplomacy. I can't recall any espionage model that I really liked that much.

I wouldn't worry about acquiring SE:V.  It was an interesting idea (virtually unlimited 4X Space conquest), but the system was just too complex for the poor befuddled AI to handle.  Not to mention it only really has one guy working on the core game, so it is still not optimized and fairly bug ridden years after its release.  Even with mods it is not that playable.

The SE series - as has already been said - has some interesting ideas and a satisfying level of complexity... totally obfuscated behind a worthless UI.  There are a few ideas worth taking - like complex treaties, actual trade etc, being better than GalCiv2's - but much of it is so different in tone to Stardock's games as to not really work.  

Of course Stardock can make effective UIs (even if you have to poke them about it) and doesn't ship unworkable bugfests (er, except Demigod), but so long as decent dipl/trade can be modded in I'm not sure what's worth taking from the SE series.

To answer everyone else's questions, the IDEA behind SE dip is good.  You can offer varying degrees of concessions, treaties, trade, use of bases, etc in exchange for similar over xyz turns.  It's WAY better than the simplistic system in GalCiv2 in that you can actually offer allies use of your starbases and then take it away when they're bad, you can lock people into trade agreements tied up with military assistance treaties, etc.  It's a fun little 'rape everyone with legal mumbo jumbo' minigame, but it doesn't save the game from its own glacial weight at all.  The way Stardock is talking about using dynasties/named characters to create a diplomatic 'landscape' is interesting and a contract-based treaty system could work in this regard.

Of course, it doesn't really work, it's overly complex for what it is, has an awful UI and layout, and the AI can't do it properly/can't evaluate 'good' and 'bad' deals.  The last is probably a good argument for why Stardock hasn't implemented such things, but hopefully Brad will decide it's a worthwhile feature in an SP-only game.

Granted, it was pretty easy to con the AI in Space Empires. Give them planets or ships that were about to be decimated by someone you are at war with, for instance. But there were a lot of varieties of diplomatic options available.

As for the implimentation... I believe SEIV was made by two guys in their basement, so I'm looking at the ideas that Stardock might be able to impliment better and I'm not judging it on the UI.

But what I really want to be able to do is get two friendly empires to go to war with each other with diplomacy and espionage like I could in SEIV. I LOVED that part of the game.