Lucario has an amazing SD set that has stood the test of time, and an NP set that can work in niche situations. Agility might look usable on paper, but it lacks the power to really do anything in this meta that LO adamant SD luke cant already do. Any competetive player with experience using luke in real situations will be running the SD set, because honestly, its the only one that can succeed in the majority of situations. (and dont talk about skarm here, it 2hkos skarm, and with rotom and heatran as popular as they are...)

Bullet punch on luke is legitly amazing. It has exactly the same power as mach punch and hits terrakion just as hard (what else do you mp anyway...) and it takes out one of the best checks to luke:gengar. I personally like running coverage over it, but with the prevalence of rak and speedscor its a really good option. If you worry about jellicent, both celebi and rotom synergize well with luke...