We are still using a reference image because we want to deploy a new system as fast as possible. The step that usually took the most time in the deployment was bringing the system up to date with patches. I know you can inject Windows patches into the WIM, but since you mentioned you are using the default WIM I guess you are not injecting updates. What also takes a lot of time is Office 2016 updates. To my knowledge you cannot inject those into the WIM because there is no Office in the WIM. The alternative might be to streamline your Office installation with updates.
But... instead we've created a VM were we installed a reference Windows 10 machine with Office 2016 and most needed C++ libraries (according to this guide: http://deploymentresearch.com/Research/Post/613/Building-a-Windows-10-v1703-reference-image-using-MDT )
The base image is updated with all the needed updates before we capture the custom WIM. We also create a checkpoint in Hyper-V before we create a new capture so the next month we can just revert to last version of the image and update it again.
So far this has worked quite well for us, but we are always open for any suggestions making it easier or faster to deploy or Windows 10 image.