Like many seasoned e-learning developers, a big portion of my experience is in software simulation. Many years ago, our options for software simulation were few; it was challenging and time consuming to produce with most tools. However, I now find that Captivate is the most sensible application to use for software training. It IS a bit limiting on the creative side of things, but it gets the job done quite well -- especially where rapid development is essential. I use Flash almost exclusively day in/day out, but when a software simulation is called for, Captivate is the right tool for the job. That said, having Flash skills will occasionally help you out, as you can add supporting media and rig up some special interactions when necessary.

My advice would be to accept the offer to invest in Flash, but go at it with the mindset that it will primarily be for dressing up or tweaking the functionality of courses you otherwise develop in Captivate.