People see the button reduction and think "Oh they made it easier to pick up!" but they're missing a few important things:
Everyone could sprint. It wasn't an optional skill.
Everyone could Purify. Not much changed about Purify except that now it IS an optional skill that you have to consider over other things.
PvP skills were upgradeable, and often worth it to do so. This is why there was PvP XP/ranks. They helped, but being low rank or having unupgraded skills weren't gamebreaking.
Ranged didn't hit like melee, and even had a damage falloff at max ranges. They were still equally deadly, but didn't have nearly as much advantage as they do now.
EVERYONE had several CC skills, most of which were quite sensible for the job that had it. In MCHs case, for having so many, they had shared cooldowns.
Many skills that were deemed "useless" in PvE held VERY strong utility in PvP, such as Sleep, MNK's One Ilm Punch (removed buffs), binds in general
Tanks were tanky. Healers were HEALERS. Yes, they could DPS, but it was low in potency and a far second to their primary role, which they excelled at.
With access to the full PvE kit, and not a fixed set of abilities, however sensible or not, the individual skill of players really made a bigger difference then. This new system might promote more accessibility (perhaps as to encourage lower leveled players to get into it), but in a system where "anyone can be good", good players are still greater, and knowledge/understanding of the PvP system or the game mode still holds more weight.