Hopefully this will generate some discussion...
Overall, I think 2019 was positive for Illinois marching bands. This can be justified by the Indianapolis Super Regional results. Illinois was represented by three bands in the top seven in Finals and had five bands in the top 20. Without searching through archives, this may be the best overall finish by Illinois bands at the Indianapolis Super Regional.
As I previously stated, Indy Super Regional results from 2019 should help recruitment for the top bands below.
I provided my outlook and questions for my top 10 bands. Since I live in the western suburbs of Chicago, I see the Chicago area bands more than bands from downstate Illinois. I also provided my 2019 comments (for comparison) when the same question was asked a year ago.
1. Lincoln Way – (2019) The band to beat, and probably will remain so. They have the largest band and the largest pool of students from their schools.
2020 – Very nice show for 2019 that was well executed with the two-color uniforms and props. Really came on strong at the end of the season. Always has a nice show. Strong color guard. Overall, I have the same expectations for Lincoln-Way in 2020.
2. O’Fallon Township – (2019) Very nice show the past couple of years, but the question is whether they can repeat. It will be interesting to see what their show will be this year. While not at ISU in 2019, they are going to several BOA competitions where other Illinois bands are performing.
2020 – Like Lincoln-Way, always has an excellent show. We can expect O’Fallon to be strong again in 2020. I do not know much about the school to provide details for a 2020 forecast. Unfortunately, ISU and the St. Louis Super Regional are the same weekend again in 2020, so we may not see O’Fallon at ISU for a second year in a row.
3. Lockport Township – (2019) Excellent visual performances. Excellent soloist performances. Watching their YouTube video of their 2018 Grand Nationals performance provides an overall perspective you do not see at local competitions. Lockport has always placed a very close second to Lincoln Way in the ISU 6A field, so this a band to watch in the future.
2020 - Again, the visual aspect of their 2019 show was extremely strong, and the addition of the drumline (albeit small) accented their overall performance. Very nice woodwind movements. Lockport is probably the best in the state at integrating the color guard into their show. Lockport made Finals for the first time ever at Indianapolis Super Regionals, so students must be excited about this accomplishment and should carry over into 2020. I expect 2020 to be another highly successful year for this school.
4. Marian Catholic – (2019) Best band musically. Always has great shows, but the show theme last year  was not as powerful as past shows. I expect better this year.
2020 – I thought the execution of their show was better in 2019 than 2018, but I think the quality of their competition is also getting better. Just missed finals at Indy Super Regional and Grand Nationals, it will be interesting to see how Marian Catholic responds for 2020.
5. Prospect – (2019) Their show is always well executed. One of the bands you don't want to miss performing. Always a very good band and will remain within the top five.
2020- The 2019 statements remain true. They do not perform an overly complex show, but their execution is always among the best. Finished 17th at Indy Super Regional and will remain within the top five within the state.
6. Downers Grove South – (2019) An excellent show in 2018. I expect they will build from this show in 2019. Another band you want to watch.
2020 – This band may have experienced some growing pains in 2019, and appeared they finally got everything together at the University of Illinois Championships. I still believe this is a band to watch.
7. Morton – (2019) Excellent all-around band. Finished 29th at 2018 Grand Nationals. They do not have the appearance of a small school band and appear to be a very dedicated group. I expect Morton to remain the top 2A band for several years.
2020 – Still the best band in the ISU 2A Field. I expect them to remain very successful. I still consider them a enthusiastic group.
8. John Hersey – (no 2019 prediction) – Started slow in 2019 but came back strong later in the season. Like Prospect, another band that executes their program very well.
9. Victor J. Andrew – (no 2019 prediction) – Andrew had a very good season for 2019. Their show was always a crowd favorite. Will their success continue into 2020?
10. Romeoville – (no 2019 prediction) – A school that had a very successful season for 2019. Romeoville made finals for the first time at ISU. The excitement was very evident in the both the crowd and in the band at ISU. A cleaner and more polished performance will improve their overall placement.