My first thought is that increasing pitching rate may increase yeast activity. Increased activity means increased temperatures. So that might actually be counterproductive.
The worst thing about high fermentation temps is fusel alcohol production. High temps also generate more esters (good IMO, but other may differ). But fusel production has multiple factors, such as oxygenation level, pH, and yeast strain selection.
Pick a yeast that ferments well at higher temps, make sure it's well oxygenated, and make sure you're rousing and degassing during fermentation. CO2 = carbonic acid = low pH = stressed yeast = increased fusels.
To paraphrase Dr. England - "Off-flavors smooth with time. So do mountains. Brew it right from the start!"
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