I'm thinking a more collaboration oriented on prem solution. Local notebooks would be very limited. Also, there is a compliance/auditing perspective that I think local notebooks would not allow for. We need more control over the data put in and how it is accessed to prevent DLP. Even just the ability to whitelist our company's public IPs with Evernote cloud would be useful. At least then, employees could not upload data in the office and download at home.
We would want the same features that Evernote Cloud currently offers, but just make the cloud/file cabinet a VM (or physical appliance in our datacenter. Similar to the way Synology and QNAP have their private note taking application (obviously not enterprise grade, but great concept). I realize this isn't Evernote's model, but I think they could find a lot of money in moving this direction because the competition that does this in the Enterprise space charges 10x as much as Evernote Business.