Hi John,
I co-authored the Residence Halls paper and can provide some insight.
The key point of the paper from an RF perspective is that hallway deployments do not work well, period. Regardless of band. You can deliver significant additional capacity by moving to an in-room, denser deployment as explained in the paper.
Now we do recommend 5GHz for this. But you can do the same RF design with 2.4GHz only if that's appropriate for your environment. You might intersperse a few dual-band APs to relieve congestion in the 2.4GHz band since you want to get 5GHz capable devices out of the way of the ones that don't have the option.
With 3 channels and high wall attenuation, you'll get OK cell reuse. The performance will be much better than what you have now because (i) the SNRs will be higher overall since you don't suffer hallway attenuation and (ii) the free space loss will be lower due to closer distance to AP.
Higher SNRs will also improve resistance to external non-wifi interference. You may also want to experiment with the "interferernce immunity" setting in the radio profile.
Don't forget that hallway APs also interfere with each other! They have a clear LOS to each other. So if you are running ARM they are going to back down power which is the opposite of what you want.