If it's your opinion, that's fine, but you keep stating it like it's cold hard fact.
It could be that I'm just a big dummy, though.
"We know we're better than this, but we can't prove it." - Tony Gwynn
Games are won on run differential -- scoring more than your opponent. Runs are runs, scored or prevented they all count the same. Worry about scoring more and allowing fewer, not which positions contribute to which side of the equation or how "consistent" you are at your current level of performance.
Don't worry, I definitely don't think Jay Bruce has any Brandon Larson in him. I think Bruce will be an All Star by the end of this decade, if not sooner. Just had to point that out though.
I'm not sure Bruce will slug like Dunn in the very near future. Take Dunn out, and there is next to no pop in this lineup. It's a bunch of average to mediocre fielding Sean-Casey-power sticks (which is nice, but lacking the catalyst that compels the overall offense to run). I think Bruce will develop great power, but not right out of the chute.
Now you could trade Dunn and find slugging elsewhere, but when you start leaving several holes to fill just one (no matter how important), you're tempting fate.