It’s a worse version of the other mobility ults (Slayer, Handmaiden, Footknight, and Zealot). They all have comparable or better CD, actually deal damage or boost damage, and/or have better stagger. They also all apply to melee classes for a reason. They can use it as an initiator since they actually want to be in melee.
For BW – who has poor melee options and spends most of her time in ranged – it’s a disengage or a situational 'oh sh!t" button. Sure, it’s helpful “when it matters,” which is to say not very often. But that’s a pretty lame use case for the ult. This could be fixed, mind you. It would just require a talent overhaul and some tweaks to the ult.
As a side note, I’m not sure comparing BW ult to non-mobility ults is really a good way to go. But even Pyro and UC ults actually synergize with their class. Pyro ult can be included as part of a CDR build (with 3-5 sec casts?) and UC directly affects her ability to maintain high overcharge (boosting melee damage) while mitigating the risk of exploding. Both are infinitely more useful during a larger portion of any given run.
What would also be nice but will never happen is to replace Fire Walk with some other spell from Bright magic:
Flaming Sword of Rhuin: gives power boost to all/nearest ally/ies and makes his/their attack deal burn dmg for a short duration. Maybe make it choose between allies or the caster (with more effect on the caster for being single target).
Cascading Fire Cloak: Deals dmg to attacking (or surrounding?) enemies for a time. Timer is dictated by the amount of overcharge. The lesser the overcharge, the earlier u can re-use it.
Just some quick thought of ideas.
I played BW again today, and afterwards noticed an interesting thing: No matter how I used Fire Walk, it always felt like I wasn’t utilizing it well. If I use it with the LV25 Talent as venting, it allows me to keep casting for a little while longer immediately, but it’s down if things get too tight and I can’t use it to make space or as an escape. If I use it to make space, I won’t get any advantage of the movement range and far less of the venting. If I use it to move, the push aspect is wasted, and again it’s likely in a situation where my heat is already low. The situation escape aspect also suffers from it needing aiming and a sudden displacement, both requiring your attention momentarily, meaning you need a little space to begin with (defeating the purpose of “panicky escape”), and your attention is momentarily away from the combat.
Later edit: So it’s hard to use as an escape for its need for aiming and disorienting nature; it can’t be used for damage as enemies don’t stay in the flames to receive anything significant; using it to simply make space is inefficient as the push strength and area is small (and still requires taking aim off enemies for a moment); and using the option of venting (the best lvl25 Talent imo) is sporadic and short-lived help at best. In short, repeat of my observation: No matter how I use it, it feels inefficient. It possibly tries to be a bit too many things, with no clear purpose to it.
And then it’s not a charge, so the aiming itself can be wonky. It occasionally hangs on ground debris or just doesn’t work on slightly elevated ground – I guess to avoid possible exploits and manipulating enemy pathing.