Personally like the proc system. Being able to have some control over drop rates rather relying solely on the vagaries of TH is a boon IMO. It also leads to increased communication during the fight as party members cover the various proc options, announce proc's needed, etc. Gives a greater sense of collaboration to a fight.

Disadvantage has always been the balance which has lead to a number of jobs being favored. But that really has been a problem with FFXI all the way along even before proc systems. Zergs always favored heavy DD, BRDS and WHMS. Kiting strategies favored ranged attackers and PLD's. Meripos favored BRD/COR/SAM/RDM parties. No matter the task, playerbase will cherry pick jobs that make it easier (then of course will complain that nothing is hard anymore).

Admittedly, having proc system on Aby, VW and Dynamis is enough for now. Hopefully SE can be equally creative with other battle systems to make fights interesting.