It is also alot less effective. I don’t think anybody wants to turn BW into “The second Pyro.” But as of now, BW is “the worse Pyro”. What BW brings to the table needs to be up to par with Pyro and UC. UC is arguably also alot more “skill based” than Pyro, since overcharge management is literally life or death, and you cannot rely on crits, but on hitting breakpoints with your overcharge damage buff. That works well, because there is a synergy between ranged and melee. BW has simply nothing in this regard. Her ranged abilities don’t translate anything to melee and her melee doesn’t translate anything to ranged. BW isn’t “tanky”, she can be made to have 100% BCR (which isn’t as useful as people make it to be imho) under certain circumstances and only when choosing ONE specific talent. Pyro and UC have all they need to fill there role from the get-go and can then mix and match into different interpretations of their roles. BW’s role is not interpreted, it is absolutely defined by your choice of talents, at least to some degree. Sienna’s CC is already very strong, no matter what carreer. The slight advantage BW gets simply isn’t up to speed to the kits Pyro or UC simply have by default. With BW, you need to jump hoops to justify your mediocre presence. The choice of talents, well… somewhat. Not that much more or less than others that are not 100% railroaded to one line of talents because otherwise, their whole kit falls apart (I’m looking at you, Slayer!).
Double firewalk is fun to use, but compare it to other charging abilities. It does pretty much nothing.
BW is certainly not a concept that is doomed to fail, but the key word is “concept”. BW needs leitmotif.