BRD used to be popular for a few reasons, mostly how well it synergised with DRG with both it's buffs and piercing vuln that it could apply, but more importantly, it was one of the only ways to get mp back for long time. Without a BRD you would just run out of MP. As it is in EW, BRD is still a RNG based job. At 90, your songs have an 80% chance of granting Repertoire, your Bites/Jaw have a 35% chance of proc'ing Refulgent Arrow. It still has aspects of it that are RNG.

I like the idea of RNG based jobs, but while they are nice when they work, if you need something to happen and it doesn't, it's just the worst feeling ever. It's like when you play DNC and just don't get any feathers, or MNK and don't get chakras, it feels like something is missing. However, if the job is designed around having a complete feeling while not getting procs, then it runs the risk of being too busy when they do happen. Another counter arguement is that proc based jobs are not skill based. They are inherently RNG, so the maximum potential of the job would heavily depend on something that can't be controlled. People who want a complex job may find that the skill ceiling is too limited, or is too inconsistent, by something that they cannot control.

Thinking back to AST, if you got AoE Balance, that was a massive dps increase, but if you didn't get it, most of your other options just sucked. But when it worked....

That being said, I do believe that having an amount of randomness can be fun, and should be incorporated in some jobs. The dopamine from when you get a proc is always a nice little thing. Like getting a Direct-Crit. It's just the amount of power that is being placed in those RNG systems have to be very carefully monitored.