Developers tend to like speedruns & speedrunners, and have slowly started building their games with speedruns in mind to some extent. While this has some benefits, I also think this can be corrosive for the high level play of games. What devs should ask is : what sorta gameplay styles & mechanics do speedrunners prefer?
It seems both obvious and weird to think about. Obviously they prefer speed, so in theory their preferences should simply be any given game's rules + a self imposed goal of going fast. Their playstyle should be a natural extension of a game's rules given that simple goal.
And yet that's not exactly true. Any given run will follow that formula, but runs don't have enough room to show player preference, because they're about optimization so the game's internal logic takes over. The thing that actually shows speedrunner preference is what happens outside of runs. Which modes the speedrunners play, which characters/weapons they pick, which categories they tend to create & populate, what gets them the most excited during runs, which types of games they gravitate towards, what kind of changes they advocate for or against in patches.
In my experience (as usual too lazy to find examples π so assume I'm full of shit & verify/debunk it yourself) speedrunners care about a small handful of things. They care about a sense of forward momentum so they will tend to prefer movement tech over combat tech which tends to keep you more stationary. They tend to like big flashy (and/or technical, stuff that makes them feel clever) time saving techniques over more granular hard-to-notice stuff. They like "out of bounds aesthetics" - anything that strays away from looking and feeling like normal play. They generally aren't that excited by anything really continuous & fuzzy like tiny micro optimizations in physics games or combat optimization until they are settled into a game.
Generally they won't care about modes that better represent a game's internal logic. For example Bayonetta's campaign is full of combat skips and is heavily reliant on movement tech, and it's played on normal (or easy even?). Angel Slayer, on the other hand, seems like it would be an absolute gift for speedrunners because it better represents Bayo's core gameplay which is combat, while allowing them to still make speed a #1 priority. And yet it's sitting there, unoptimized. To me this also explains the surprising lack of overlap between racing game players & speedrunners - the two are connected but not to the level you'd think. It's also why speedrunners don't really like patches that fix skips, even though this often creates far more opportunity for demanding, granular optimization in the parts that can no longer be skipped.
If you're building games around speedrunners, you will pigeonhole yourself into creating a much more limited playstyle than it might initially seem. Not to mention, speedrunners will generally deal with whatever the fuck as long as they like the game overall - this is the same group that will play slot machines in Mario Kart or Goldeneye after all.