Okay so I am sure these points have been made by now, but I would like to restate them to remind people that others have done this too.
To counter claim number 1, I am only going to say this. Space Empires V was done in 2006 and it has way more features then this game does, the graphics are not nearly as good but it has the shipbuilding, a very very extensive tech tree, and it also has the create your own race feature too.But the biggest difference is that it has all of that with multiplayer. You lost nothing with it added.
Claim number 2 is that very few people want the multiplayer feature added. This could not be any further from the truth if you wanted. The problem with forums is that the most outspoken, or rather the people who are the loudest tend to win. In this case here, the people that don't want it shout out "NO" more often because they hound this forum enough to make it seem like they have more people. And as for the polls on this matter were done wrong because they ask not if you want multiplayer but rather if you want it versus having new game content added. That is the same as asking "do you want me to give you a really expensive car or do you want a job? Oh you want the $200,000 car, then I guess most people in the world don't want jobs" The poll was set up to make it sound like no one wanted the multi player added in. But I know for a fact that there is a huge market for it, and the longer the game stays single player online the longer it will be before this game is able to pick up. Look at most turn base games out there, almost all of them have it now.
Claim number 3 if I am understanding it right is that they design team would not have been able to do as much fluff in the game, they would have to focus on other aspects instead. Umm, you do know that games like Civ 4 has mini cutscenes in it right? You build a wonder or found a faith and you get a cutscene for it. But again this i a hollow claim because cutscenes don't take away in a multiplayer game at all, if anything it add too it. Imagine if you are playing online and there was a cutscene for when you build the very first dreadnought and the person your at war with gets it, so you also see the cutscene, well now your in trouble and you got a little something to help add to the feel of it. Fluff works well in single player but it can also be just as good if not better in multiplayer.
Now I am no fool and I know how much code you have to add and change in order to make a game multiplayer, and I also know that making a game multiplayer is also a gamble on it being a success or a fail. I also know that it can be a bit expensive, but if it is true that the game was set up from the start to easily add it in, then most of the time and effort will be lessened because of this. Don't assume that just because on these forums that you don't hear a lot of people saying this, that most people don't want to have this feature added. I know many people that said they will not switch from Civ IV, V to this game because it lacks the multiplayer feature.