When business managers demand new or improved business capabilities, those demands need to be rationalized. There is no easy way forward here; it's a continuing negotiation between IT and the business. The business will almost always want more resources than IT can reasonably deliver.
CIOs must ration the demand so that it matches available capacity in terms of investment capital, time to market, people and skills. This is where IT can and should pitch its business partners to provide funding for new capabilities for standardization and platform coherence--not because it makes life easier technically, though it does, but because standardization and coherence provide the business with more capabilities for its money and gets them deployed faster.
Next, the CIO should look for the minimum solution footprint that will satisfy new and existing aggregate demand. This is where common business services emerge. Working with customers, it's best to identify what can be shared and what needs to be unique for each specific capability being sought.
A primary asset for the CIO is a group of solution architects who understand the business well and know what available technologies make it possible to deliver. CIOs should also leverage corporate and industry standard business process models to understand and optimize the flow of information and work.
Although CIOs would like to discover that every business capability can be satisfied by assembling common solution elements--think horizontal capabilities such as messaging, directory services, identity and security--that's probably not going to happen.
Some of the elements will be common to only one or two business areas, or unique to a single area--think vertical solution capabilities such as credit checks, warranty management or underwriting. As the architectural review effort proceeds, the business and the solution architects must put a value on each unique element because uniqueness will cost more in development and lifetime total cost of ownership.
When done--it will probably take several iterations to get a workable agreement--there'll be a solution architecture with a supportable business case, a required level and schedule of investment and an expected ROI.