Since there has also been a discussion going on about this in another thread, where it seemed to me it isn't clear to some people why so many want a sandbox mode with everything unlocked right from the start OR, which would be my preference, the possibility to unlock things within the sandbox mode: I think we have to imagine this like for example a new installment of the Call of Duty series. Call of Duty, in most cases, offers a single player campaign, a zombie mode and the multiplayer mode. It's the multiplayer mode most players are coming for. The other ones are there if you like them, but you can also play only multiplayer and completely ignoring the other modes. Why? Because those modes are not connected together. People love to progress solely in the multiplayer mode, unlock new weapons, skins, gadgets etc. and all this happens by playing on and on in the multiplayer.
Now, imagine you could not unlock new weapons and such in multiplayer mode, imagine it would be required, if you want to have other things than the starting equipment that is, to play through the campaign in order to unlock new weapons for the multiplayer. Wouldn't that be silly and completely senseless? I'm sure players would be up in arms (no pun intended... but also not avoided, hehe). But well, that is, if you extrapolate this core principle and transfer it to JWE2, actually the exact way the game is working.