The fairness aspect is a big issue. Not trying to avoid the original question, but the following is about to be lengthy enough. The UIL's 4A classification itself has issues as it is the classification with the least number of schools (I believe this to be correct). If I counted correctly, there are 188 football schools in 4A and 202(boys) and 203(girls) basketball schools. The 188 football programs causes an issue that I am not sure how to deal with. Unless there was a decision to pull 10 or so schools down from 5A and do the same with a pull up from 3A, the numbers simply leave a mathematical issue before we even discuss logistics. If the UIL allows the largest school districts to keep all schools from that district in the same athletic district (ex. HISD - District 11 D1), you are left with 180 schools for the 31 remaining districts (whether combined as 1 conference or split into 2). If one would then make things as equal as possible, you are left with 6 districts with 5 schools and 25 with 6. This would still leave (if using the split conference method) of 2 regions have 2 districts with 5 teams and 2 with 6 teams. This still leaves only 6 teams staying home in those regions with 16 still entering the playoffs.
Even with this, there would definitely be even more travel involved than already exists.
There just are not simply enough schools in this classification for it to have an equitable set up and pulling from the others would likely cause problems for those classifications as well. Maybe, a better answer for this classification is larger districts with some byes in the first round of the playoffs? However, that starts a whole new argument. We may all have disagreements with the UIL, but I simply do not envy the task they have with realignment.
Side note: If you look closely there is quite a bit of shifting of schools to different regions from football to basketball to make the basketball alignment more "equal".