Funny, went through the same quandary w/ my 90 w/ the same bladder setup. Mine was inop and the nozzle (early style) was broken. Turned out the plug was disconnected. I fixed that, cleaned and lubed the wiper gearbox, replaced the nozzle and blade and it works great. No leaks. That said, I may have used it once in a year...
I'd fix it, also gives a reason to get into the door, touch up any corrosion, cracks from the spare, etc. Good rainy afternoon job.
BTW George/RDS has the early nozzles if you need one...kind of hard to come by in the States.
'85 90 2.5NA
'72 SIII 88"