We are rolling out SharePoint in our company because people got sick sending Excel files to each other when doing bids and tenders, etc. From what you describe

We are rolling out SharePoint in our company because people got sick sending Excel files to each other when doing bids and tenders, etc. From what you described, it looks like you you are going from a perfectly working model to unknown at best. I don't have a lot experience with SharePoint,but at least its sharing model is very primitive. SharePoint site members have access to content by default and then it's just explicit sharing with other groups/individuals. More granularity would be so much helpful. I found integration between MS products to be a blessing and a curse at the same time. I was trying to demo how you can go from SharePoint to OneDrive to local storage on the PC.. There are multiple ways how to go about certain things and it's not always obvious. Centralised document storage, live document editing,version control are nice things,but they need to be used for the right use case, otherwise it's going to be painful.