I think this is a bit of a loaded question. The value I've seen with SWOT is that was a way for people to DOCUMENT relevant headwinds/tailwinds that they should think about or incorporate as part of their strategy.

It's not that SWOT was anything magical. It is simply a tool to get people thinking and discussing the pluses/minuses etc. in the context of what they want to achieve. People find the S/Os much easier to articulate than the W/Ts, but they do need to focus on all 4.

In the end, I find they come out ahead of where they would have been had they not done it. It's not a panacea, but it's not a worthless exercise either.