A few years ago a Chicago paper had a computer program draw the 50 Chicago Aldermanic districts based on only 2 criteria:
Equal population
As compact as possible
The result was that the racial/ethnic makeup would not change at all. The only thing that would change would be protection of powerful incumbents.
In both 2001 and 2011 I did the same with the census data for the IL State House and Senate and Congress. The single biggest change would be the lack of protection for incumbents, both R and D; And the loss of power by Boss Madigan.
It would change both R and D districts to be competitive... many more purple districts. Even when Republicans are in the minority in Illinois the incumbent in a safe R district does not want run in a competitive district and have to work for the votes ... even if the many purple districts could mean an net increase in R districts.
As the Republican Chicago City GOP Chairman said: I’d rather have control of the minority party than just be one of many leaders of a majority party. I can get more jobs and contracts from the majority party when I control the minority party.
It's not ease of voting, nor similar constituent concerns, nor ease of the office holder to service his district.
It's about making districts that can be controlled to assure a job for life for the congressperson. Slimes. Incumbency is a huge problem and anything that can destroy it has my support.