It's true, engi are underpowered in pvp compared to same levels coms and ops. We got less damage and stats like dodge and armor than they do.
On the other hand, some seem to do rather well (you should read morfic's guide on that matter, will be more insightful than i can be).

Though, you almost have to get the very best weapon and plat armor (for dodge) to stand a fair chance. Let's just hope devs will change that in future update.