You want to justify some IT spending for cloud-based platforms. Your CEO or board has asked for a business case, and you've been scrambling to create one. Of course, you'll include obvious items like capex versus opex. However, most business cases miss three important concepts:
1. The value of agility
Yes, again. The problem with agility in a business case is that it's hard to define, as well as hard to assign a dollar figure. Agility rarely gets into cloud business cases.
But agility should always be considered in a cloud business case, even if in the abstract. If you can scale a server cluster in seconds without driving hardware and software buying cycles, what is that worth to the business? In most cases, I suspect it's worth a lot.
2. The cost of people
Yes, the obvious people costs are included in cloud business cases, but many enterprises' talent pools lack the skills that need to be factored into the business case. Because of this unfamiliarity with the skills necessary to build and maintain a cloud deployment, they miscalculate required resources. For example, you might estimate it will take 10 people to monitor and manage systems on public clouds, though it could easily be twice that amount.
The trend seems to be to underestimate the people needed to drive a successful cloud implementation. As a result, the actual budget has cost overruns compared to the business cases estimates. You must understand the staffing needs and the cost of people who have the needed cloud skills -- they are not cheap.
3. The value of devops
Organizations that implement both devops and the cloud get a "1 + 1 = 5" value. Most business cases don't use this formula, so they miss a lot of money that will flow back into the business, once the business moves to cloud computing.
Devops and the cloud are treated separately in most cloud implementations, but they should be linked. That will increase the apparent cost in the business case, but it will also demonstrate the much higher full value generated for the enterprise.