Hi
the GRC project is totally IT driven.
I get why you are having to drive this - especially when you have to respond to audit requirements and your focus is on support processes.
However, GRC is all about business risk management - Governance, Risk and Compliance (well internal controls). The GRC System is just the tool to manage this. Without business buy in how is this going to be successful? Who will review business process to determine what a risk is? Who in a senior leadership position will determine what risks are acceptable? Who will determine appropriate controls, report on them, and more importantly enforce them? Who in a leadership position will champion the project and support why a user must work a certain why (including access removed from them)?
I get that you are focussing on a POC and trying to minimise cost but what happens post POC? I've given recommendations where I've said don't put in GRC until you sort your process and culture. I've done this as much as the innner techy in me knows I won't get to play with a new toy because without all the business buy-in you will have a system built and deployed that gives you a false sense of security when it comes to managing access controls.
Another way to look at the SP issues - what happens if it's on ECC and the functional team (aka the business representatives) demand an SP increase for their functionality? They proceed to increase SP and now your functionality stops working.. which then impacts the business as you can't process their access requests and give them timely access to the system (assume this is your business case). Are your basis team going to tell the business that they can't have the SP stack increase because IT needs the system on a certain level and they need to wait until next time it's compatible?
Good luck with your POC. I understand it will allow you to use the tool and check what will work for the business. If you are still undecided on system landscape post POC, take care in having that decision made for you. As you go down the POC path and time runs out the project may move from POC to design/build and now that it's working there will be reluctance to move it to a separate system.
Regards
Colleen