We would not want to. The Darkness is our enemy. If anything, we would use a Throne World just to establish a point of origin for an attack of some calibur. Creating a Throneworld also falls within the bounds of the Deep. This is what essentially creates a lot of the encounters, blights, and portals to and from. Guardians being in their could be disastrous for both sides.

There hasn't been any real indication on the requirements on making a Throne World other than you having to be strong enough to carve it out (which isn't that descriptive). You can be strong physically like Crota and Oryx, or magically like Nokris and Mara Sov, but there's no known bar to what has to be achieved to do so. Our Guardian likely has the requirements to carve our own throne world, but it's redundant when we have our Ghost who also fuels our powers.

We are not bonded with either of those weapons. Yes we are [b]borrowing[/b] the power of the darkness with the unique perks however the key factor is we are NOT [b]physically[/b] or [b]biologically[/b] bound with these weapons. We are only momentarily bound to the touch of malice when we make an active choice to use its final most powerful shot but as soon we sheath the weapon we are no longer affected by its power. With the whisper the user is bound to nothing at all, the side effect of killing with that weapon is that xol feeds on the death for his own gain. To access the power of the ascendant realm and the sword logic we would need to give ourselves on some type of biological level, for example the hive have a worm inside them, they cannot live long without it or access paracausal power, another example would be the trueborn awoken whos soul would be literally half light half darkness.