Arenado is three years older than Bregman, so theoretically getting Arenado for 3 years would be like getting years 4-6 of a Bregman contract. In that case, Bregman for 6 years would be preferable to Arenado for 3 years. I don't know if they can get Bregman for 6, but if they could I think it would be a good deal.
As for whether the timing is right, they were in the playoffs last year and they have the best pitcher in baseball with two years left on his contract. The timing seems right to make a push if the right fit is available.