Can't speak for Fire/Fire, but from watching some Fire/Psi doms in action, hot feet provides a ton of damage. It was doing something like 1/2 the damage over time that PSW did.
Active (Freedom): Setna (Ice/Psi Dom), Arram (WP/KM Tank), Tesmiel (Elec/SS Tank), Astredax (Robot/Dark Mastermind), Operative Vidali (melee fortunata)
Retired (Virtue): Gaav (Inv/EM Tank), Baqra (Fire/SS Tank)
COOL! That is good to hear, while it has being doing some nice damage at the level I am at now (20) Just seems to work more for a, "Oh crap guys are trying to get in Melee Range with me, I'll fix that!" type thing, but I do admit I don't have it slotted for damage at the moment, just End. (Still waiting to get SOs)
I think I will hang on to it then and see how it looks when I can starting really slotting it up, besides it's not like I am suck with it if I don't like it 
Hot Feet is pretty worth it if you're consistently in melee range. I have mine slotted with a little extra slow (Damage/Slow IOs frankenslotted in) so anything in range is at the -move cap. They don't uncluster enough to be notable, and the avoid effect is useful protection. Plus yes, the damage is nice. It's more useful if you're on a low AoE power team, but I wouldn't skip it either way.
My 50 Dom is a Fire/Fire, and I find Hotfeet to be very good. It does quite a lot of damage over time. It's significant, even on teams.
It's also an endurance hog. Even though I'm well into permadomination, have Stamina, and have a recovery unique slotted, I still find myself running dry once in a while before Domination recharges when I have this power on. It's not a huge deal, though. I could probably move one more slot to it for a 50 endurance reduction IO and compensate for it entirely (and in fact may have to do this when the Dom changes go through).
Wouldn't skip it for anything, however. It's quality.
The Ballad of Iron Percy
Thanks again guys! I will hang on to it, and see about slotting it up for Damage/End as soon as I finish off Flashfire and my AoE hold 
hotfeet on a /fiery is very good. FE is 30 seconds of +85% fire damage and it isn't very hard to get it up half the time.
I'm worried about how the supposedly heavier endurance cost of Dominators with the changes will interact with the fact that Fire Control is already an end heavy set, not even counting Hot Feet. Then add in Hot Feet. I'm nervous. Oh well.
Anyway, yes, Hot Feet definitely adds to my Fire/Thorns (50) and Fire/Psi (50) damage. It's a good power. It does crush the end bar though.
Lewis
Random AT Generation!
"I remember... the Alamo." -- Pee-wee Herman
"Oh don't worry. I always leave things to the last moment." -- The Doctor
"Telescopes are time machines." -- Carl Sagan
Milady gives a pretty vivid account of her lvl 22 fire/fire on test.
linky
(last post on the page)
I have been working on two Fire/* Doms, one a Fire/Elec who is almost 30, and another which I am liking much more a Fire/Fire. With the Fire/Elec I Hot Feet does come in handy, but the way it's looking I might end up sticking with the Fire/Fire. The thing is I am not really seeing the need for Hot Feet on this Dom. Does it come in handy later or can it totally be skipped and not even looked back on?