There's no real advantage to "passive" sidestick systems except simplicity: less things to go wrong. And by now this design has been proven to be highly reliable and successful.
Yet despite its success, the A320 sidestick is literally 1980s technology. A bunch of springs and dampers -- it's ancient tech by today's standards. But there were no other options back then. Airbus had to fight hard to get digital FBW accepted by civil aviation authorities. They needed to demonstrate a fail-proof system. And a big reason Airbus pushed so hard for certification was because the chief proponent of the sidestick system was none other than the CEO's son, who had been a military pilot.
Only now in 2015 has technology advanced to the point that "active" sidestick systems with full force-feedback are becoming a commercial possibility.
Gulfstream will become the first civil aircraft manufacturer in history to use an active sidestick in the all-new G500 & G600, which will incorporate a new system designed by BAE.
It's just a matter of time until other commercial aircraft manufacturers will adopt this technology as the new standard.