makattak observed,
What is missed in that is that to control the formation of the districts, you have to win control first.
Not necessarily. Depends on how and where you pose the question. Putting it in terms of "the enhancement of democracy," that is, one person, one vote, can sometimes change things.
Example: My recollection is that the business of changing selection of State Senators by the State Legislators to
direct elections by the populace has been regarded as dangerous. After all, isn't a "democratic" selection of Senators by the entire population "better?"
But some "representative republic" devotees see this as an example of the danger of rule by a "50% +1" pure democracy. It throws to the wolves the original theory of balancing the "democracy" of the House of Representatives against the two-per-State Senate.
This is analogous to the theory behind the Electoral College's selection of the President, which balances the populous States against the more agrarian States.
So beware of those who tout "democracy," in the 50% + 1 sense.
There are others who disagree with this so-called "danger," though.
This quote has been widely mis-attributed to varous people:
"A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy."
But it and its variations contain certain elements of truth, disunirregardless of its original author. See
https://en.wikiquote.org/wiki/Alexander_Fraser_Tytlerfor a discussion of it and its original author.