More than just SMART, the purpose of goals are to provide focus. A useful guide is the How Might We question, as it incorporate the what, the when and who in a succinct manner. In addition to this, I have found the Modern Learning Canvas useful in regards identifying particular points of innovation.
This is something Vivian Robinson touches on in Student-Centred Leadership:
When goals involve new challenges, how can you possibly know if it is achievable, if it is realistic, and how long it will take you to achieve it? In the absence of such knowledge, it may be better to set a learning goal or a broader performance goal that expresses your shared commitments and helps keep you focused.
The problem in a world driven by data and accountability, we are often uncomfortable with embracing the wicked and fussyness of the unknown.