I've used Warwick a couple of times and i like him. His ability to heal (his passive and life steal) makes me want to use him again, also makes jungling a lot more easier. I also prefer his simplistic style, no complicated abilities and such. Is there any champion that has passives/abilities that resemble to Warricks?

Are you saying like the passive heals you and the abilities are simple?

try garen he doesnt have lifesteal but he does have good health regen and u can build some lifesteal which would go great with his high attack damage

I'm not familiar with Warwick but it sounds like you might like Nunu.

i'm familair with ww and i know exactly what you mean! i play with champs such as, garen, yi, teemo, etc.

also try out new champs and see which other ones you like, a good jungler is yi, similar to warwick, in fact i use the same runes that yi uses for ww.

Skarner > Warwick on almost every level.

Warwick and Cho'Gath were my original champs, and Skarner is like Warwick v2.0 on AoE steroids.

Olaf is fairly similar in my experience. I don't really play Olaf except for when he is free though.