Although the idea of getting in early makes me nearly quiver in delight, I am with those calling for the soft launch idea to be reconsidered.
There are very few titles that have ever had a successful soft launch. The only one I can think of was DOTA 2 and this was largely due to the huge community that DOTA had before DOTA 2 development. When it comes to MMOs I doubt it has ever worked to the advantage of the game.
I believe the main reason MMOs fail to get off the ground is twofold;
Firstly, obtaining a large enough active community to support an MMO environment (one that doesn't feel like a ghost town) requires extensive advertising and marketing. A "hard launch", both physical and digital is a great avenue for pre-launch advertising especially in the case of digital format when a popular platform like Steam is used. The wait and anticipation for launch events are very handy at creating hype.
The dream game you have described in the past as Crowfall is particularly prone to this. Because you want to market to so many individual communities and have dedicated servers in smaller countries (like Australia) you will need to attract a relatively large player base from each region so if advertising isn't effective some regions will begin as the classic "ghost town" of a dying MMO.
The second problem is always having the content to keep people active. Some MMOs fail because they look healthier then they are. At launch subscription and activity tends to be high, however, if there is not enough content activity can drop rapidly but still appear fine in the number of members. This tends to lead into a vicious cycle of dropping activity and subsequent subscription cancellations until the game dies.
Both of these facts discredit the idea for an MMO soft launch.
Another problem that players don't like entering a new game they just paid for at a disadvantage that cannot be overcome by playing more or better than other players. If you allow the backers to enter earlier and do not reset the servers then they will have a time advantage over everyone else. This is compounded by the way you level in the game. By the time you open it up to more players the early backers will be months ahead in training and new players can never really catch up.
I honestly believe a soft launch will be the end of the game.