Pay-by-usage software pricing? Yes please!

This post (and its title) is inspired by:

• A thought I had a few weeks back
• A blog post by Duncan Jones of Forrester (Pay-per-use Software Pricing? No Thanks!)

Consider two individuals:

1. User A: Needs certain features available only in Photoshop CS5, but uses them infrequently
2. User B: Uses many features of Photoshop CS5 heavily

Should A pay as much as B to buy a Photoshop CS5 license? No, in my opinion. It's neither fair, nor value-based, to quote Duncan Jones.

(However, I'm against the "limited duration" and "limited number of times" models sometimes used to implement pay-for-usage. From my observation, these models act as a constant "concern/distraction layer" in the minds of users trying to complete a task, forcing them to also focus on their usage, hurting productivity/quality and killing the fun of using software. Examples include limited minutes on phones and data-transfer limits in Internet connections. You may give less features, but don't limit their usage.)

What solution do I propose? None as yet. I'll think about this some other day when I have more time.