Moon, I respect your thoughts and opinions probably more than anyone else's here but at times you tend to throw a little BS around in the way of obfuscating facts. You're right. UZR/150 is not WAR. However, UZR/150 or "Range Factor" or whatever else those trained observers or computer models want to call it is a prime factor in determining DWAR when then gets extended into WAR. In the case of JBJ, whose primary strength is his defense, his deflated UZR/150 makes a significant difference in his WAR and whether we want to admit it or not, nobody puts together a cognizant argument against WAR and therefore WAR is God. (I will never understand why, when baseball is comprised of offense and defense, OWAR + DWAR doesn't = WAR but that's a whole 'nother issue. Maybe that's too logical, but then again I thought math was logical.)
Anyway, Of those five players you mentioned whose UZR/150 are better than JBJ's only two of them - Dyson @ 1.3 & Martin @ 0.1 have DWAR in the positive numbers while JBJ's deflated DWAR is 0.4 and his WAR is 2.0. Only one of them -Dyson - has a positive WAR, and he's behind Bradley!
Dyson being the pick of the litter of those five earned $3.75M last year. Assuming he gets a raise to $5M from the Sox we've given up even more offense to save $5M. Is that enough to justify weakening ourselves up the middle? And that's IF we land Dyson. We can probably save even more money if we sign one of the others but you do tend to get what you pay for. Ugh.
BTW, all WAR values are for 2019
I wholly admit to being (maybe too) optimistic at times but I'm still hanging my hat on the fact that while he's playing for someone else there are going to be some posters here saying, "How did we ever let that guy go ?"