This platform is helpful for sales teams, HR dept as well as educational institutions. Should we focus on only one vertical..say sales teams and then introduce other verticals. For sales team our coaching/ role play app is ideal to evaluate sales reps knowledge and ensure they pitch in the right way.
It's best to define your initial MVP's persona as narrowly as possible, and learn from your tests (initially small scale) to make it work well for them, and only then expand to other verticals if necessary.
It sounds like you think it will work best for sales teams, so start there, get some data on its effectiveness / demand, and tweak it so it works really well. Then you can build from there.
If you'd like to discuss best ways to run initial testing with your specific product send me a message, I'd be glad to help out.