Thief viablie?

I was discussing Morrowind with a friend a few days ago and we've always had our fav. builds in any RPG: I am the diplomatic char or silent thief he's the big tank/berserker/"Me big me smash your skull" type. So the argument came when we discussed if one can very well play the game as a thief, ignoring even lockpicking for the alteration skill and only using marksman for fighting purposes. Also it would be harder to play since raising sneak is a little difficult (without blocking yourself in a corner and sneaking ofc).

So the question would be this: is it possible to play a thief, with alteration and illusion as minor skills and only with marksman? I know that some parts in the game are combat oriented so is marksman and a few support spells enough to make it? Also this is a matter of playing the expansions too, not just the main game. What other skills might be useful besides the typical ones like light armor and the ones already mentioned?