While we can choose which field to order by when searching in advanced mode:
… we cannot choose whether we want to order ascending or descending.
Adding orderdesc modifier would easily make it possible:
order:likes is already descending, right?
So what you want is “the opposite of the normal order that this term means”.
Not sure about this, but… How about order:-views to start at 0 and go up, while order:-latest starts at the oldest?
struggling to think of use cases for orderdesc:likes or orderdesc:views, though I am open to possibly adding order:earliest (its quite rare to need though)
We should find a way to allow for opposite ordering for any ordering type (kind of a universal way of doing it), then easier to remember and use.
You never know what one could come up with 
I’d use orderdesk:likes to identify which type of material is the worst in terms of people likes and not create similar topics, or not include them in the lists.
orderdesc:views might possibly indicate topics that need some more useful information to get more attractions from organic search.
I think there might be more use-cases I can’t think of, why not just make it possible with a single operator.
I want this feature in order to support an “inbox” use case for processing forum traffic: I have a search that I want to sort by least recently posted (so that I can work down the queue of posts awaiting a response), and I can only get most recently posted (afaict).
You might want to consider using the Unanswered filter: /latest?max_posts=1.
However, I did also write a PR to add this sorting option:
Taking suggestions as to what the name in the dropdown menu should be, I don’t really like “Oldest Update”.
Estaba buscando una forma de ordenar los resultados por más antiguo (orden cronológico ascendente, añadiendo estos términos para futuras búsquedas en meta…) al buscar dentro de un tema.
No pude encontrar “Ordenar por Publicación más antigua” (solo está Publicación más reciente), pero sí probé “Ordenar por Tema más reciente” y funcionó.
Creo que entiendo la lógica, pero las palabras son un poco contraintuitivas en este caso particular.
Una opción de orden cronológico ascendente/descendente sería, para mí, una buena adición, a veces intento hacerlo, y lo he hecho en otros foros que lo permitían. A menudo más por diversión que buscando información específica e interesante.
Además, me pregunto con qué frecuencia la gente ordena por Más reciente, en comparación con el valor predeterminado “Relevancia”. A menudo uso “por Más reciente” en muchos foros.