Easy rebuttal: Rogue agent. Rogue =/= Not a killer. You're using the term "Rogue" incorrectly. Also: Thieves just steal? Burgle = Theft. Con = Can lead to theft Steal = Theft Exploit = Can lead to theft Scam = Can lead to theft Never said you're playing wrong. Simply stating you're using the term "Rogue" wrong. Look at it this way, if you were saying a pencil was an airplane, I would correct you, because a pencil isn't an airplane. This is that exact same situation. You can play how you like but you're using terminology wrong.
And you're being unnecessarily pedantic. Plus, your anology of the pencil & airplane doesn't work here. "Pencil" and "airplane" are both very stable terms, with almost no room for misinterpretation. "Rogue" can be a noun or an adjective, and its meaning is considerably more vague.
Words have many meanings. D&D rogues kill stuff. Doesn't mean everyone described as a rogue
must.
Anyway, on-topic. The OP seems to want to only perk "Thief" skills - Light Armor, Speech, Sneak, Pickpocket, Lockpick, Alchemy.
I think it's definitely doable. Even if you never perk One-handed, getting the Assassin's Blade perk makes those daggers a good way to open a fight, if not end it outright. Shadow Warrior means you can get those sneak attacks indefinitely (afaik; I haven't taken it yet). Even Archery can be used - not perked, but used in conjunction with Sneak and Alchemy it would be pretty effective I'd think.
Regardless, the style of play would be very different than any other character, as you have no direct way of dealing damage among your perked skills. An exception here could be getting the Poisoner perk and reverse-pickpocketing poisons on enemies, but I don't know how effective that is.
What I'd try to do for melee is get Shadow Warrior, get those Pickpocket perks to steal weapons and equipped items, steal everything from an enemy, and then do some crazy repeated sneak attacking.
But really, the more fun way to go most of the time would be to avoid combat as much as possible. Definitely makes for a more thiefy experience.