This sounds like a fun mod, but a serious playthrough with the Bethesda released game that involves all the rest of the aspects of the game where you are a Lich? No one but necromancers and maybe some VERY few unsavory sorts would speak with you, but worse than not speaking with you, would attack you on sight. You would not be able to complete any of the main questlines, or almost any of the minor quests normal people would otherwise give you, or be a part of society in any sense, and would basically just wander around pointlessly killing things in the wilderness and dungeons as a Lich. I'm not passing judgment on if this is what you would like to do, but there is just no way this would be part of the stock game. You are somewhat more limited as a vampire in other installments, but not to the point you would be in being a lich.
In some other fantasies, Liches can disguise themselves with illusion spells to appear normal visually, but usually in said fantasies just about any other physical contact or magical effect that comes in contact with them ruins the disguise. Liches in TES have never exhibited this type of capability though... they are always just monstrous killers hiding in ruins.
Unfortunately, necromancers and vampires consider liches to be abominations. (it was represented in game through a massive disposition drop for full liches towards both necromancers and vampires(-100)) Now, as stated above, a fresh lich could look a little more human. Now, if liches use the Phylactery method, then their horrid bodies are because of the poisons rauaging them while their is no soul or regeneration being done. Eventually, the body dies and the poison halts its destruction.
Of course, being a lich may be an abomination to the natural order, but it could have some purposes for the good. If you cannot complete a duty in life, and are unable to bind your soul to the world, then its a feasible method. Seems to me, most that become a lich lose their humanity and awareness, same as most that gain lycanthropy of any form (as seen in bloodmoon, they lose their minds)