I recently started oxygenating with pure oxygen and controlling fermentation temperature tighter and I have noticed more malt character in my beers. What used to be hefeweizen that tasted like clove and banana with a touch of beer now tastes more like a nice malty beer with a hint of clove and banana in the background. On my oatmeal stout I could actually taste the malts and oats rather than that distinct english yeast character. I didn't change anything about my mashing.
Taste your second runnings when you sparge. Mine taste thin and somewhat "husky." I think that it detracts from the malt flavor. Acidifying my sparge water has helped.
Thanks for the tips. I have been thinking about oxygenating my wort with pure oxygen for a while. Maybe it is time to switch.