I have a warrior, who uses a 2 handed sword wearing heavy armor. I've manage to get my sneak up to 30. And I'm only level 15 right now. I keep hearing how great the Dark Brotherhood quest line is. Do I have a chance? I'm half way through the Champion line right now.

Thanks for you opinions.

Yeah, you can do it well enough. You'll get a set of Light Armor at the start of it, and the option to get a better set somewhere in the middle, but you don't have to use it.

There is a Perk in the Sneak skill tree that muffles your armor, amongst others. As long as you keep putting Perks into Sneak, and you complete the Contracts I don't see why a tank couldn't do the Dark Brotherhood Quests. Remember there was an Orc in Oblivion who was a member of the Dark Brotherhood, and he didn't Sneak for anything. So it's very possible for you to do it.

And you heard right. Coming from a Dark Brotherhood (and Assassin characters in general...) fanatic, the DB questline in Skyrim is amazing.

sure you can.
have fun.

i wouldnt say amazing, but you can run around bashing skulls, that nord in there didnt neak either and he was a duel weilding beat face. but a few quests have to be done in stealth or you may glitch your quests, so listen to what the quest giver tells you.

This my friend is the beauty of the game. Anyone can be a member of the Dark Brotherhood if they so wish. Even your heavily armoured Warrior.

I personally prefer to do the questline with a stealthy character but that's just me.

Of course you can do it.
All characters can be Dark Brotherhood. Mages, warriors, clothes wearing, light armoured, heavy armoured, big clanking juggernauts, anyone.
Just wear the shrouded armour to do the killing and you'll be fine.
You don't have to wear it but it helps a lot.

You don't have to be able to sneak well even. You will gain sneak by default, from all the assasinating, over time.
My mage killed lots of people by hiding, turning into a werewolf, then killing them and running off.
I never got caught once.
But if you are going to sneak up on people, use a dagger and keep a dagger handy.
Nettlebane is fine, you'll get it from a quest at some point anyway.

If you want to wear your heavy armor you can just wear the shrouded boots and you won't clink.

I don't recall any of the quests requiring Sneak. Which one(s)? Keep in mind:
1) I had plenty of Sneak skill on the character with whom I did the DB line so I may have gaffed it off when they told me I needed it.
2) I didn't do any contracts outside the main questline.