I think all of these problems could be solved by a fixed time control for the entire game in correspondence.
Some players want to play fairly quickly and want to play in tournaments that will finish in their lifetimes. A one month (750 hour) time control for all your moves in the game, with no increment or vacation, would be good for them. If you spent more than a day on most of your moves you'd probably end up timing out, but you'd still have time to analyze some positions in detail if you wanted.
A two month (1500 hour) time control would be a bit more leisurely but still lead to a reasonable expectation for when the game/tournament will be over.
The "average time per move" for players isn't a very useful statistic because it's based on past performance.
When seeking opponents for a correspondence game, there are settings for how fast opponent you wish to have.
However the choices are just fast, faster and fastest.
How about adding choices for us who do not need a reply within hours, but do not wish to wait a week either?
Adding "normal < 24h" and maybe a setting "faster than 48h". I don't mind that an opponent takes a few days now and then, just as long it is not five days every move.