Step One: Make a new weapon AND a reskin
This is the same amount of work needed to create a weapon and a reskin of that weapon later, but w/ more returns.
Step Two: Announce that the reskin is a reskin of a weapon that WILL come out later, and sell it a ways ahead of time.
The announcement builds hype for the new weapon that will come out and allows for an additional release later.
It also swings the development in a positive direction.
The special weapon will then serve as a beta period of sorts.
Step Three: Release the "normal" variant.
This will actually expand upon the game, allowing everyone to strive for it and enjoy it.
It also plays heavily into marketing- in today's day and age, "free" games come across as being scummy.
Following the lead games like TF2/Dota set by NOT selling out completely would set Spiral Knights apart.
This is especially prevalent due to the general reputation that MMOs hold.
This is about the mixmaster, isn't it?