One of the biggest problems I encounter when playing a rogue/assassin type class in any elder scrolls game is that I feel gameplay is more time consuming that any other class. You have to sneak and use more tactics when fighting because you can't go toe to toe with enemies like a fighter type class or blast them with damage like a wizard.
Initially I always focus on using a bow because in the beginning your sneak will not be high enough to get close enough for a 1h stealth attack. However it is important to use you 1h and take damage when possible because I have encountered the problem in the past where I have weak light armor and 1h skill because I have neglected to level them with the other abilities. I spend my points in 1h, Archery, Sneak, Light Armor, Illusion, Enchanting, and Armorer. However I do rely on Alchemy and Lockpicking but I do not allocate any actual skill points to these areas because I do not think they are really of any use. The sole purpose of Enchanting and Armorer is to improve my gear and enchant it with class beneficial spells. Also remember to level Illusion so you can use spells like frenzy to turn enemies on each other if you ever find yourself surrounded out of stealth.
I read a post online where a guy suggested having several different daggers when playing as an Assassin. He had one that was enchanted to drain magic for fighting casters, one to drain stamina for fighting warriors, one to steal souls, and two others that do fire and frost damage. You can further elaborate with whatever you see fit but this gives you the ability to have gear to use against any type of enemy.
I feel it is extremely important to plan out how you level your rogue and what skills you are predominant with. As stated before make sure that you are either training for light armor and 1h or that you take time to allocate non stealth combat with lower level enemies to make sure these skills don't fall behind. I have never played any other class than an Assassin from Daggerfall, Morrowind, Oblivion, and now Skyrim. I had to scrap my first Assassin in Skyrim because I didn't level him properly and he would get bent over at higher levels.
As for an RP aspect I tend not to overload my stealth perk because there comes a point where it is so ignorantly high that you could sneak past Jesus himself. The fun in the game for me is using poisons and well planned gear to tackle enemies that would dominatrix you if you faced them toe to toe. If I am feeling like a complete nerdass I sneak into my home undetected and change into common clothes before walking around town. If I receive a quest to kill a bandit leader I try to sneak through the entire fort and kill him only. Stealth class opens up a whole new world of game play that I personally believe is second to none. You can really see how bethesda made them game and enemy NPC interactions and conversations in detail when they do not realize you are there. If you have anymore questions I could go on for hours so feel free to ask.
- Dave