Most of the events are cross server, you're never really competing with anyone in your own server except for 3 things, GNW, Ranked battle & Nine Tails- and it comes down to whether you're bothered by not being in the top 3.

It depends if we're talking about 40k between you & the top 3 or 40k between you & the average player, if it's 40k between you & the average player, I'd think about restarting personally because I'm a little competitive & I'd assume you wouldn't be here asking if you weren't also.
I'd also base my choice on what you have, will you lose a lot of good ninja by restarting?

If it's 40k between you and the top 3 then it's fine, as p2w'ers will always be paying to win on a new server or an old- the top person on my server is 40k ahead of the person below him & 50k ahead of me, just to give you perspective.