My use-case is similar to yours. I rarely connect my current 15" to any external monitor so right off that bat it eliminates the 13" for me due screen space for large sketch/design documents. I also plan on some light video editing that is more personal stuff rather than client so I would need some GPU power for that. Base model for the 2017 15" MBP is my current top choice. I think the improvements are marginal between that one and the top line one in the 15".
My use-case is similar to yours. I rarely connect my current 15" to any external monitor so right off that bat it eliminates the 13" for me due screen space for large sketch/design documents. I also plan on some light video editing that is more personal stuff rather than client so I would need some GPU power for that. Base model for the 2017 15" MBP is my current top choice. I think the improvements are marginal between that one and the top line one in the 15".