It doesn't have to entrench the political parties, depending on the system used. For example the people tasked with drawing each district could be selected fro

It doesn't have to entrench the political parties, depending on the system used. For example the people tasked with drawing each district could be selected from the general public by sortition, i.e. like jury duty. These people would be given access to every tool and expert help they need, and if they wanted to just rubber-stamp the suggestion of whichever party they support, then they would be free to do so. A slightly more deterministic process would be to generate a list of all parties (or independent candidates) who received more than 10% of the vote at the last election, and allow each of them to draw a number of districts in proportion to the share of the vote they received.