I hope there will be a mode that lets us build more freely like making each wall, staircase, window, roof, etc...in any shape we want (like building houses in The Sims) but I have a feeling there wont be

Give it at least a month before anything remotely looking like that is on the mod sites. Personally rebuild Junktown, Hub or another FO1 / FO2 settelment mod I would like to see. Find / build the Cafe of Broken Dreams in FO4....

Cafe of Broken Dreams http://features.cgsociety.org/newgallerycrits/g07/56707/56707_1143799763.jpg.

I guess I should hold off on building my settlement until I get a mod that allows me to do proper clean reconstruction then.

I'm not tearing down Sanctuary Hills to build Decrepit Shanty Town.

All I want is a fort like place that I can live in and have a band of raiders that work for me that I can send out to attack caravans and stuff, so I really hope Bethesda allows you to have a raider settlement.

Nah, build it with the style you have available then tear it down and build it up again when you have what you want. The Todd said you can build and then tear down anything you want.