I took it, the extra damage it gets from fiery embrace is nice. Haven't gotten to the epics yet, but still am going for fire/fire/fire as well.
I took it not just because of the damage boost, but also because I also went with combustion and incinerate. I have it on almost all the time, between domination/consume/stamina, blue isn't an issue, so extra damage is about free. It's a handy way to finish off foes w/o wasting attacks on slivers of health. It also looks great for the 'walking fire hazard' thing.
The way I do it is Flashfire>fiery embrace>firecages>bonfire>fire breath>run in>combustion, attack foes as they burn. The bonfire is fine with renewal of the fire cages as soon as they're up, and has the side effect of giving you a fight practically covered in fire. It makes me giggle happily every time. 
can't wait for RoF/fireball....
Hot Feet.. Grab it. It is very nice. It is not only good damage for an aura damage power, but it slows the enemy to keep them under control easier and also makes some minions run away from you in slow motion - hence damage mitigation.
I run up to a mob, flash fire, hit fiery embrace, jump in the middle, hot feet goes to work, hit combustion, then fireball, mob dead (minus bosses that I clean up). All this with 3 ticks of hotfeet that helps as discribed above.
I've recently rolled up a new dom and am absolutely loving the burny mayhem. He's a Fire/Fire and ultimately I plan to get Fire epics as well. However, I'm torn about Hot Feet. It's a fantastic power and I fully appreciate it, but it wouldn't be strictly necessary in a pure Fire dom, methinks. I see his contribution to a fight as Flashfire-> Embrace of Fire-> Fireball-> Fire Breath-> Rain of Fire-> then on to single target attacks and holds. This will do scads of damage, but the positioning necessary might perclude maximizing Hot Feet.
Of course, you can play it either way and in the end it's my playstyle and my choice, but I'm curious to sound out others who have already experimented with this. Does anyone have any insights or play experience that leads them to lean one way or the other?