An often asked question involving Enterprise Architecture (EA) is "What role should EA play when organizations are implementing an ERP ?".
Let's look at the core role that an ERP plays in an organization (which typically enables the transaction management and ensures compliance in one or more domains covering order through cash cycle and down through SCM & logistics). While that's a large portion of the operations management for an organization, it is not the value differentiator. In many cases, the ERP vendor and/or organization has attempted to "extend" the core features into these value differentiating areas. This is where things get tricky when organizations need to move with "agility" (whatever that means...) or need to merge operations (M&A) or divest or (gulp) integrate with other organizations. Most integration topologies are now being built atop the embedded ERP middleware solutions. This gets tricky also since the number of interfaces and the complexity of these "exchanges" is growing exponentially due to the pace of business and the opportunity to collaborate. And, we haven't even begun to talk about "Big Data" (which bleeds over from operational to value differentiation) and presents an order of magnitude more complexity.
I would think that an organization would want to engage EA to influence the positioning of the ERP and guide the configuration of the underlying models used to meet the operational needs and enable the value differentiators for the organization (now & into the future). The challenge for the organization is how well it understands this balance and whether it is prepared to embrace the investments required to manage it (or simply follow the vendor and be managed by the vendor).
The challenge for the EA (based on how they are positioned in the org.), is how well he/she can communicate the complexities, challenges, and opportunities to obtain understanding and buy-in from the organization to ensure the right decisions are made to preserve this balance and sustain it as the pace of change accelerates.