Low Kick from Slaking = 10 DPS * 290 base attack stat = 2900
Counter from Machamp = 13,3 DPS * 234 base attack stat * 1,2 STAB = 3700
Based on this rough comparison, I'd say no. Don't have my spreadsheet for more exact calculations now.
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But as a generalist , with hyper beam , it will be a Blissey killer lol
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Pokebattler simulation has Low Kick Slaking killing Blissey in 56 seconds with more than 50% hp left, which is very good, but certainly nowhere near broken.