How much terrain are you using? Warzone is a game that works best with lots of terrain. I usually try to set up my tables with no more than 12" of empty space between any 2 terrain elements, with the average distance being closer to 6". Use the terrain you have, a little smoke, and a little luck and you should be able to get into CC.
As for 1st edition heroes, while their base stats were too high the real trouble was in the special equipment, special abilities and weapons. I remember building a Shamrock hero for imperial who had 4 actions (Command Helmet), Move of 6 (Cybernetic Legs + Fast movement SA) and a 75% chance to ignore all wounds (Shamrock SA + Combat medic) and wielded a Nimrod Autocannon, at least I think thats how it broke down it was a long time ago, but anyway you look at it this guy was too powerful.
