Backbreaker is just a free shove prone. Shoving prone should already be a part of Shove Action, which should be available whenever I need it. It's basic. Why can I only attempt to prone someone once per short rest and only if I have a weapon that gives me Backbreaker?
Does Backbreaker also deal damage as part of an attack action? Or is it a bonus action weapon ability that only knocks prone?
And of course my old favourite: being drenched in acid gives you -2 AC for a few seconds, after which your armor and you(!) apparently regenerate.
This makes a bit more sense if you think of it as a character realizing their boots are melting and trying to get out of the puddle, focusing on that and thus temporarily reducing their ability to dodge attacks (effective Dex penalty for purposes of AC). In Pathfinder they'd be flat-footed.
