Here are some of the things that come to mind that can be changed relatively cheaply and quickly.
1. Let ground control issue ground instructions, and issue clearances. This costs nothing, and does a lot to minimize the frequency congestion on tower. Also, this meets the international standard. Optional, add clearance delivery frequency.
2. Departures off of 18L and 18R at the same time. Yes, it can and is done in the rest of the world without radar. The procedures are many decades old, but why they're not used here, I have no idea.
3. Establish interfacility coordination of estimates and flight plan data. This is so basic to ATC, that it truly is amazing that it's not done in Nigeria, and we have pilots giving this info over and over via the overloaded airways.
4. Split the approach frequency into two, perhaps along a line of runway 18R and 18L. Yes, a transmitter would have to be purchased, but I'll bet that the airlines themselves could be persuaded to finance this directly, and quickly.
5. Use the radar. Note I left this close to last. For a group that has never used radar, just turning it on won't make things smoother. Like piloting, using radar is an learned and acquired skill, practiced over time to proficiency.
6. With radar, use parallel simultaneous approaches. This is probably the single most costly of my ideas, because it takes some specific radio hardware, and a dedicated controller to monitoring the approaches. Some aircrew training issues, also.
7. Train the controllers to use 36L/R when wind conditions dictate.
I intend to meet up with the controllers at LOS this month so that we can mutually understand the issues that we face. My background is two decades of ATC in California with FAA, working enroute center (Oakland), approach (SoCal), and tower.
If you have some specific suggestions, I'm all ears.