So, if I'm understanding you correctly, you're leveling the agent for "easy keybinds" (whatever the hell that means), and you're sacrificing a plethora of extra abilities, stats, bonuses, and procs that would make your self-proclaimed impressive agent infinitely more impressive?
I'd say just go Operative, pick the Lethality tree, and only pick the passive bonuses if you really want to be a "pure" agent. Just going straight agent though will get you turned down from almost every Flashpoint or Operation you attempt, and people will probably just leave the WZ when they see just a plain ole' Agent on their team. Either way you're lacking the raw power of a Sniper or the incredible utilities of the Operative.
I honestly didn't even know that it was possible to skip your advanced class until I saw a level 40 Trooper in a WZ. Just a trooper... not a commando or a vanguard. Needless to say he ranked pretty low on that scoreboard. You shouldn't be able to leave the fleet without picking an AC; you're needlessly inhibiting yourself and doing the people who team with you a disservice.
EDIT: Just for fun, I went ahead and made a Lethality Operative, only picking the passive bonuses and no extra abilities. He'd still be under-performing, (since he's missing most of his bleed effects) but it's still better than a "pure" Agent. http://www.torhead.com/skill-calc#40...MZGrrzbMG0GM.2