I think the problem of a EULA is that most EULAs are written in English which presents a problem for a majority or users. No? I agree that being as explicit as possible is good, but I also agree that erring on the side of restrictive is good for business. When you err on the side of restrictive you can always make case-by-case exceptions for clients who reach out to you with specific needs. But if you err on the side of less restrictive you will find it difficult to back track.
Additionally make the user feel that they can reach out to you if they need questions answered.