I'd love to see the cold startup time (that is, when both Overwolf and CurseForge aren't running) improved. I'm using a very high-end machine (Ryzen 9 3950X, 64 GB RAM, Samsung 970 EVO NVMe SSD) and cold starts are taking about 10 seconds.
It looks like the majority of the cold start time is spent launching Overwolf, as launching CurseForge with Overwolf already running takes only about 2 seconds. So, as a user who is only interested in the features of CurseForge, about 80% of the startup time is for a feature I don't plan on using.
For comparison, Twitch launches from a cold start and displays a complete interface in just 3 seconds on my machine.