Nah dude, Rotom-F got nothing on this, I get it, even though from BW onward the power creep fucked things up 86 still isn't slow like arct, as a matter of fact, if you look at Rotom-F during various generations, including DP where it's ghost, (but the speed stat is the same anyway and you still have Rotom-A as a choice scarf user) you'll find scarf as a set, and you at the very least need ok or above speed to consider such, or a very specific niche such as magnet pull Magnezone which can't even outspeed Starmie sadly, for example:
Rotom-A outspeeds Breloom, Heatran, base 80s like Mamoswine or Dragonite, adamant Lucario, Cm3 Suicune, Gyarados and so on, Scarf was very useful in order to check dd threats, as none of them outspeed Rotom, and it also gave you the ability to check a great deal of speed boosters like Dragonite, modest Empoleon, Gyarados etc.
Bw is when it got cursed with ice type, but it's immune to ground and got Volt Switch so at least it could try being a pivot in lower tiers, xy ou had its speed tier do an important job in checking Altaria 70% of times, sm did pretty much the same, ss ou I don't use rotom-f, but I used several times Rotom-h or w scarf, where you can do a bunch of nifty stuff like outspeeding and tricking scarf on Kommo as it setup, outspeed Gyarados at +1, neutral scarf darmanitan, non scarf Dragapult, Gengar, Dracovish etc, all this wouldn't be possible if you had a terrible 55 base speed. Point being, yes, Rotom-f became a trashmon the moment it gained ice type, but lack of speed was never one of its fault.
Oh right, forgot, the famous volturn strategy popularized in bw, it had stuff like Landorus, i then t, celebi and Rotom-w, most of the time scarf, again.