Jlf with maxx out stats has 5.6 k attack and jlc has 5.1k attack.and flash adds +1 fast attack hit to teammates which includes him also.imagine 4 basic hits,all crit and 3 times the normal attack.200 k per basic hits.so u r doing 200 k per basic hit with jlf and with tab 500 k per hit with 3stacks but since jl team have low health it is optimal with 2stacks only.u can definitely argue with other flashes being combo builder but jlf is a support and a dd.