Your marketing actions are directly tied to your vision. They are one of the means you can use to achieve your goals and get closer to what you want to be.
Reviewing your overall vision might be necessary in order to better understand where you want to go. Step back and take a moment. Think about where you want to be in 10, 20, 50 years. Think about what products/services you want to build. Think about how you can make things change.
You do need to develop an overall vision for the company, one that includes every aspect of your business and strategy. A great vision needs to inspire your collaborators. It gets you and everybody else in the organization coming to work every day to be part of something bigger. A vision should also be sound and achievable, you have to truly have a realistic chance at getting there.
Having a clearly defined vision makes dealing with opportunities and threats much easier. Instead of responding to them as they arrive, knowing what you want to achieve and where you want to be helps when considering options, and ultimately when taking decisions for your business. You will see that knowing whether those opportunities lie within what your vision will help you take decisions.
But a vision is not a strategic plan. The vision should state where you want to go; the plan tells us how you're actually going to get there. Planning work should only begin after the overall vision has been decided and communicated thoroughly. Making a plan without a vision is your best chance at going nowhere.
Plans can change while the vision is more of a long term aspect of the business. But that doesn't mean that you cannot change your vision. You can modify or even have a brand new vision, especially if you feel that your original vision does not apply to your believes, or is simply outdated, or at best, if you have achieved it and need to have a bigger vision.