Kevin Drum covers current efforts toward nonpartisan redistricting in California. Nonpartisan redistricting is good for democracy. The right political muscle and a jittery hand can turn a 51% majority in the state legislature into an impenetrable, permanent majority.
American neighborhoods are becoming far more uniform. Not just the infamous Woodbury beige, but inside the homes as well. People with similar incomes are living in similar neighborhoods; people with similar incomes, similar jobs, and similar backgrounds tend to have similar world views. One result of this trend is naturally safe districts.
This means that redistricting does not imply more competitive races. Salvador Dali could draw the Minneapolis districts and you're still not going to have competitive races.
The conflict comes in balancing the precious few competitive districts that actually exist. Bipartisan commissions are more likely to keep their thumbs off the scales in these toss-up districts -- and it's exactly those districts where electoral mischief is most tempting.