I think you will like riding the 690. Here is my experience for what's it worth....
The thing that made me truly appreciate my WR250r was purchasing a 690r. The 690r is an amazing bike and the power is addicting but the WR is now my "gravel road trip bike". I never had any trouble with my WR and I had constant issues with the KTM. It wasn't that the KTM is not a reliable bike, it just seemed to require a lot more attention. I guess it is just the price you pay for the performance. The WR is a 2008 and the 690 was a 2009. At my skill level (or lack of skill) I am more comfortable taking the WR into harder terrain than the 690. I thought it could replace the WR but it really didn't work out that way for me. I do definitely miss having the power of the 690r sometimes.
I decided the extra maintenance and expense is worth getting a higher performance bike for trail riding so I bought a KTM 350 EXC-F. This bike makes me smile when I ride it where the WR is fun but work in trails. However, I wouldn't really seriously think of taking it instead of the WR for a multi-day trip on gravel roads.