Well that's a large part of the problem honestly. People didn't want to try or learn PvP then. It was never hard. Never. But SE made no effort to teach, and the playerbase didn't, and generally still doesn't know of the resources the community made for themselves all this time. I personally wrote 2 Frontlines guides, and made a few video tutorials showing why I say some of the things I say, like MCHs not fully loading before entering battle. And STILL I see and hear MCHs fully load up before the gate comes down.
During the early days of the Garo event, I remember plenty of times seeing advice defiantly refused; the now-famous "you don't pay my sub" meme. Even now too; had someone tell me "Nobody wants to hear your suggestions, Lace", as I was telling them not to drop off cliffs to reach a large ice teeming with enemies while we only had one healer. Can you guess what happened?
You perhaps have the mistaken impression that the vets want things to be tougher. We don't. Learning how to PvP was never tough. I taught a guy 3.x PvP MCH in the course of a week, and through duels. In no time at all, with practice and effort on his part, he plays well enough that I have to caution my team if he's on the other side. He also learned to be a good healer in 3.x too. Maybe he's a prodigy, but I saw the work he put into it, and I see how it paid off. Even I wasn't so amazing at first, but I simply pushed myself and faced all challenges head on. Either I won or I learned the hard way. A lot of the veterans did. But rather than want the bar raised, we just wanted people who were willing to learn what we could teach with far less struggle. The PvP system did not need to change so drastically to facilitate this.
It's worth noting, before I forget, that even if BRD was easy to play, the bigger picture was that many BRD players didn't like the change. They didn't ask for it, and BRD wasn't so difficult before that either.