1. It needs to be a Wing Commander game. I'm sure Jumpgate: Evolution, Eve Online and Freespace: The Potato Chronicles are all excellent games... but I just don't care. I want to live in a familiar universe rather than one created solely for the purpose of taking my $15 a month. I'm sorry, I know this rules out a number of excellent games... but it's just how it is for me.
I think the same goes for "regular" MMP games: I never understood why Everquest was so popular, since Everquest wasn't a 'real' thing - Ultima Online was set in the fantasy world I'd dreamed about exploring further for years already (on the other side of the same coin, I never understood the draw of World of Warcraft... because no matter how simple and fun the game might be, the existing Warcraft fiction was just so stupid).
I think we're about to see the first great generation of adapted MMORPGs (since UO, anyway) -- things like Age of Conan and Warhammer Online seem to be taking settings that are valuable for what already exists and giving them the love they deserve.
(Note to someone important looking for loaded MMPRPG settings, make Robin Hood Online. I want to play that. Or Dinosaurs Online. That would be so rad.)
2. Define personal identity correctly. This was the singular problem that ran through the early 'space' games - the ones that dried up the market. Here's the deal: there's a balance to be struck and you can't just tip everything in one direction. That is to say that you both are and are not your car.
Earth and Beyond and Star Wars Galaxies screwed this up in opposite directions. The former dropped characters entirely, while the latter left out spaceships (at launch). Those were both crippling flaws. Our theoretical MMP space game needs to have a traditional setting for character interaction - on bases, planets, etc. - over which a space combat engine is placed. Now, the degree to which this is developed can vary entirely... it could be anything from customized avatars in an environment that lets them communicate and choose their missions/ships/cargo/etc... or it could be half the game, with personal combat and weapons and so forth. I prefer the first of these, because...
3. Simple doesn't suck. Every fan-created 'Privateer' wishlist in the 1990s was full of silly pie-in-the-sky suggestions. I want to own a base! I want to run an entire fleet! Giant things that add little fun in exchange for vastly changing the game dynamic. Don't let this happen. Remember how you felt when you first saw Star Wars? Was your reaction that you really wanted to be Han Solo... or that you really wanted to be Han Solo's limited liability corporate sponsor? Owning a giant fleet of ships and running an entire star system and blargh blargh blargh is neat until you actually think about how it would work.
4. Think really, really, really hard about ship customization. I'll be honest: I don't like what they came up with for Privateer Online (2). The moduler ships - in description, anyway - were a lame concept. They destroy the *style* of the thing, which is a lot more important than people understand. Pick your cockpit/wing/engine/fuselage/etc. sounds like a fun idea that lets you have 10,000,000 possible ships in your world... but in reality it'll just look like a mess.
Again, here, do as Privateer - lets have specific ships that can be (now visibly) upgraded with better engines/generators/turrets/etc. This keeps the art styled, it allows players to identify ships in a reasonable fashion and it enables a competition among pilot preferences. Let players cutomize colors, nose art and even what's in the cockpit.
5. Start small. Bigger isn't always better - give me one sector of space that's really well done instead of some massive setting that encompasses everything but done only moderately well. Give me twenty fantastic bases to explore instead of a thousand carbon copies of two standards. Do this well and I'll happily by new content to keep building out the universe.
6. Make space interesting. This applies to all future space games: one of the problems with space sims is that just plain space is *dull*. It's like an airplane game without the danger of hitting the ground or a worry about physics that might trip you up during a battle.
Our design team needs to sit down and plan to implement a huge list of 'stuff' to populate space: black holes that suck you towards them, nebulas that block your systems, asteroid fields, minefields, debris fields, ion storms that can zap your fighter, pulsars that force you to fly through their shadow, wrecks of ancient ships to explore, planetary atmosphers, fry holes full of monsters, etc., etc. You also need stuff to do - savlage, mine, ship goods, dogfight, hunt, etc. That all has to be worked out in a manner that I don't feel has been yet. In short, the lions share of our game should be played in space mode - so it has to be *cool*.
7. Reasonable death mechanics. This remains my number one worry and I haven't solved it even in my head yet after all these years. The game needs some kind of gloss to explain why after Deathkiller33 blows up my Centurion X that I'm transported back to a base and not heavily penalized. I think this requires a lot more thought than they give it for the Priv Online 2 concept, with clones and government stipends... it should be a basic element of the game design. Are fighters and upgrades so cheap that losing them doesn't suck? Do you not lose them at all? If so, why? Do you automatically eject? Is there a space sorcerer who brings you back to life? This needs thought.