The problem is with people flocking to the meta when there are tons of viable builds. Just because your build might not be quite as strong as a meta build doesnt mean you wont be as effective with it. Meta builds are for the top 1% of players to push endgame content more effectively then their direct competetors.
GGG cannot possibly be expected to balance dozens of builds, every league, at full endgame gear potential. There will always be one or two builds that stand out above the rest. If they balanced all the passives, ascendancies, gems, and gear to have exactly the same potential every league, it would take them 100x longer to come out with content, and there would be no incentive to try new builds because the effectiveness potential would not change from build to build.
I like that they are changing the meta from league to league the way they are because it incentivises people trying builds they would not otherwise try if they werent meta. Additionally, this league there are tons of builds that are exceptional, and different than exceptional builds from last league, while not quite meeting the potential of the meta builds.