This is coming (very) late to the game, but I think you may be looking at DW Fixer the wrong way. I was down on him, too, until I started using him regularly, and kept having him put together awesome damage combos. Regular Fixer is all about (frustratingly slowly) building up your tools and styles until you have a great combo, then tweaking it with different tools/styles to fit the situation. I look at DW Fixer as (essentially) a deck full of 3-damage one shots. Don't wait to load up a combo -- use the styles/tools right when you get them, as needed!
So in the scenario you outline, regular Fixer plays Jack Handle, and hits all non-heros for one. DW Fixer plays Jack Handle, but instead of holding it, he Bitter Strikes and destroys it -- since the destruction of the card comes AFTER he does damage, the Jack Handle lets him do 3 damage to all non-heroes! (If you have Galvanize, Syncopated Assault, or other damage buffs going, that's 4-5 damage to each non-hero on your very first play -- enough to decimate Voss or Dawn's forces).
With DW Fixer, almost every card in his deck is essentially a 3+ damage one-shot with extras. He can do 3 damage every turn, with some added effects. Bitter Strike with Riveting Crane--suddenly that 1-2 DR isn't there anymore (Goodbye, Huginn/Muninn!). Bitter Strike with Dual Crowbars - 4 damage to first target, 5 to a second. Bitter Strike with Jack Handle -- 3 damage to all targets. Bitter Strike with Tire Iron -- destroy any target with 5 or less HP.
And mind you, that's only if you burn your cards everytime you get them. If you add heros that let DW Fixer get in card plays/draws, or wait 1-2 turns to put a tool/style (ANY tool/style) in your hand, the one-shots become more powerful. Let's go back to your original scenario: On Round 1, DW Fixer plays Jack Handle, then sits out/waits. Now on every subsequent turn, Fixer can play Charge to get 2 damage to all non-heroes, a style (or use Meditation to get a style, or even Harmony if you want to burn it) to get 3 damage against all heroes, or Bloody Knuckles to get 5 damage against all heroes. The only things that really stymie him are Grease Gun (but that helps everyone else), or Overdrive (because he has to burn a card everytime he uses Bitter Strike, and he can't burn Overdrive).
This thread inspired me to do my own thread on tricks/hints/combos with DW Fixer -- any comments/thoughts are welcome: https://greaterthangames.com/forum/topic/clever-thoughtsideascombos-for-dw-fixer-7974