Here is my question I am a level 42 tank that weilds a 2H and wears Dadric/heavy armor. In the past I have left the DB alone and did not play because my charcaters tend to play the noble warrior type who think thieves and assisns are just the lowest level of people. I just joined the DB for the first time and find it silly that I need to change armor and tatics to do the simple hits being assigned. Money is no issue so I pay a fine with every hit. What issues am I going to have if I just go in and waste someone and then "pay the fine" and walk away? i will just go to another dugeon and and recoup my cost of doing business and move on. I think its bada$$ to just walk up, not say anything a lay a 2H upside a head and try to walk away (kind of a Taratino "Kill bill" thing).
This may be more appropriate for the spoilers section since I can see a lot of answers getting into spoilers. But I will give a non-spoiler answer. The way you want to play the DB questline seems like a perfectly valid choice to me both from a gameplay perspective and from a lore perspective.
Frist, the gameplay. I haven't done the DB questline in Skyrim myself, but from what I know about the game, there are no real penalties for your actions and you cannot get (EDIT: permanently) kicked out of any guild. Bad game design IMO, but that seems to be the way the game is designed, so let's go with it. You will probably miss out on some quest rewards by bludgeoning your way through the DB questline, but that's your choice.
Second, the lore. In Oblivion there was an Orc member of the DB who finished his contracts in the exact way you are describing. His dialog was some of the funniest stuff in the whole game. So, yeah, bashing your way through DB with 2H and heavy armor and making a huge mess in the process has support in the lore. Go for it!