It's an extremely bold move anytime a company has to raise pricing, and I actually admire WHMCS for doing it.
I've always thought their product was under-valued but much of this can be contributed to the crowded market in the early 2000s. Look how many "good" web hosting software companies actually stuck around. Most everyone that was around in the late 90's/early 2000s are gone. They under sold their products and couldn't keep up with the support and development costs.
Personally, I was REALLY concerned how this would effect us as a Reseller, since we provide a free WHMCS license with some of our packages. However, we've made adjustments on our end, and along with their new licensing plugin things are actually going quite smooth.
I know there are some that are never going to be happy about the increase in price and I'm sure they have reasons that make sense.
But looking at the industry in a long-term perspective, I believe they're moving in a positive direction that will allow them to continue to be innovative all while keeping up with their current support and development needs.
Just my two cents .