Revives not that necessary if you know the strategy, tho you have to bring some just in case.
personal experience, i used 2 revives on johto e4 and some elixirs. my team consist parasect, absol, gengar, and gyarados, 2 other party are for dummy pokes. parasect for spore and switch to absol for sword dance and sucker punch or gyarados dragon dance, they deal 1 hit ko.
there are many way to defeat e4 beside mine, find one that suit your build.