I will point out that this suggestion is to
return Metronome Battle to ranked, as it was from the start. As someone with over 7000 confirmed battles in Gen 7 (
/rank flametix, gen7metronomebattle
) from 1000 to #2 and back again, I can say from experience that search time wasn't a big deal, even being common to juggle multiple games at a time. I would say the ladder actually made it easier for me to find enjoyable battles.
I have noticed that team quality and consistency is really the main difference between the ranked and unranked state. The game hasn't changed for people who use uninvested vanilla mons like Clefable and Togepi, but many former players took the game seriously thanks to the ladder giving it meaning.
A cool ~175 people have a bottomed 1500/1499 elo. I believe making Metronome Battles ranked again would bring some of that popularity back and increase the playerbase. Would OU be more enjoyable if it was just about pummeling random Ash teams, or losing from the other side? Even if someone has no idea about the meta, today they still have a solid chance to win against a meta player because the teambuilder maxes out EVs automatically. More recent QoL features include showing every legal mon/item/ability and not marking Metronome as illegal.
These features lower the 'information ceiling' for people, and the thing is that these didn't exist for most of ranked's existence. People managed to have fun back then, and it's only gotten easier to play since.
Personally I've never seen the ladder dead; there's always someone on at every time of the day. I would say this makes Metronome Battle more popular than a dead ladder, or at least popular enough for me to get a game whenever I want. When checking the battle counts around the start of writing this post/reading the reply, I usually caught the battle count at about 8-9 with a peak of 12, with plenty of unique users. Even back as a ranked format, the worst experience would be like getting a 1000 player after half a minute of waiting, and that's more about the 1500s and/or if you've just finished a battle and everyone else is occupied. I believe there is a feature that tries to pair you up with a similar rating at first, but expands the boundaries after some time. It also helps that it's an easy format for the average person to get into, being simple to learn and popular on YouTube.
To sum it up, Metronome Battle is currently in good shape with a consistent audience, helpful teambuilder features, and historical precedent for success as a ranked format. I believe that having a ladder would lead more to play and add enjoyment from its existence without any serious tradeoff.