Great posts as always from @macskull, you should be given a forum title!
I may have incredibly low standards, but I think this game has so much freedom in it that you can make anything work in any situation. Literally any AT in any situation can be unbeatable given the necessary time and dedication to achieve it. You want to be good in arena? Watch and learn from the community, follow the meta (damage is king, cap hp+absorb, etc.), learn effective voice communications and keyboard shortcuts. You want to be good in zone PvP? Gather your friends or in-game acquaintances and work as a team (just like in PvE). Every ability in this game has a counter (I welcome evidence to contradict this statement). Nothing worth winning is achieved without effort - put in the effort and you will come out on top.
I would argue that the above statement holds true across badging, solo-ing content/TFs, leading trials/hami raids, etc., as well.