2. An RPG Spacecraft Must Look Cool.* If you wanna sell a ship - either to your players or on the open market, it must look cool.* From all sides.
Actually, you do not want every ship to look cool. Especially in RPG's... if players get an incredibly cool ship, getting them an upgrade may be next to impossible...

5. The more powerful the weapon, the more limited the rate of fire/number of shots/ targeting accuracy/ something else that keeps it from breaking the game. No one wants their Player running around the galaxy in a Star Destroyer. The Mellineum Falcon is almost as bad.
Actually, the Millennium Falcon is a good example how to make an overpowered ship balanced... What I mostly remember about it was it's rather grumpy hyperspace drive which failed at at least one crucial moment. If the players want that super-powerful turbo-blaster... let them... just let it blow up in their face once in a while, or make it break down right when they are about to deliver the finishing blow. Overpowered but quirky components can actually make it work. Just make sure you add so many faults that the players will sometimes ask themselves why they didn't buy the dependable peashooter when it once again fails.
Though fantasy, I once introduced a 'hat of ideas' into my campaign. The players thought it was awesome, and it indeed does have great uses... however, they misinterpreted my words as 'hat of good ideas'... I never said that. The hat still has a lot of potential, but they don't really use it that often.

7. There Are No 10'x10' Rooms in Space. **** Observe the case of the International Space Station.* The ISS is the single most expensive construction project in human history.* This includes things like the Manhattan Project, the Great Wall of China, and the estimated cost of the Great Pyramids at Giza.* The total cost of the ISS is*greater than the Gross Domestic Product of some industrialized nations.
**** I mention all this so that you will understand my point about extra space in space:* The habitable volume of the ISS is roughly*that of two 18 wheeler trailers.* There simply is no spare room in*spacecraft.* All realistic spacecraft are designed for minimum weight and volume.* Accept this and go on.
Hell yes there are, but just as my players in D&D are currently content with their horses and wagons, they dream of owning dragons or mastodons as mounts. Remember, you're talking Science FICTION. Having room available or not, is a design decision. If launching a 10.000 ton spaceship costs as much as refuelling a truck or something, no, space and weight won't be an issue. If building a craft capable of travelling to Mars in 5 months costs billions, yes, room and weight WILL be an issue.
I do have some problems with comparing those great historic monuments with ISS though, not strictly because some of those monuments have cost thousands of lives, but the level of technology, and the amount of people supporting the project may also be a problem in comparing. If I divide the total cost of ISS by the amount of people supporting it (through their governments), the cost per person is about 157 dollars (total cost = 157 billion, divided by about a billion people). Let's say 200 dollars. It's not the cheapest thing ever. But people had to work a YEAR as tax-payment on the Great Pyramids of Giza during construction. Not all of Egypt's people, but compared to that 200 dollars, ISS suddenly sounds cheap. A LOT of projects have placed a far greater strain on the available resources than ISS.