Well hold on a second guy's.....I know Bethesda said in allot of games that you don't need to delete your saves or game data,but here is why I think you should consider starting from scratch when a new patch get's released,let's say you went to an area where you run into a bug that you had to work around to finish a quest or something and you do that and then the game saves well the game just saved a bug/error that stay's in that save file and bug's are bad since they can corrupt your save file and cause more problems down the road in your game.I always restart a new game after a patch because that way the patch get's installed from the beginning meaning it fixes all the problem spots and does it's job properly.
Whilst this is true, and your method of starting afresh with a new character when you get a new patch is valid, we need to clarify a few things here, and add some context to the discussion;
1. The OP is purely asking about erasing 'previous patches' before updating to a new patch. Savegames and the issue of how bugs can affect them, has not been mentioned so far.
2. With reference to...
let's say you went to an area where you run into a bug that you had to work around to finish a quest or something and you do that and then the game saves well the game just saved a bug/error that stay's in that save file and bug's are bad since they can corrupt your save file and cause more problems down the road in your game.
This depends upon what you have done for a 'workaround'. Assuming you are playing on a Console (Xbox, PS3), then any 'workarounds' are likely to be within the logic of the game. Workarounds allow you to progress through a quest normally, and avoid bugs that are preventing you from continuing with a quest. As this is within the constraints of the game, you won't 'generally' be specifically saving any bugs or errors into your game.
3. Where starting afresh with new characters with a new patch is benefical, is when you have actually saved 'corruption' into your savegame. But how do you know this? Well, if you experience things like 'vanishing chunks of background like, water, scenery', or experience repeated lockups whenever entering a particular area, these are caused by bugs in the game engine corrupting memory, (and potentially) objects/NPC's. If you see this happen, and you save, this will save corrupted data into your savegame. It is in this case that your savegame is unfixable, and you are best off restarting the game. Savegame corruption like this can (in the majority of cases) be prevented, by reloading your most recent savegame. You will lose the progress up to where you currently are, but as long as you save frequently, you shouldn't lose much time. I have used this technique over the last few weeks and have a corruption free savegame. For example, when you see threads reporting problems of repeated lockups when entering certain areas of the map, or chunks of backgrounds are missing, their savegame is permanently broken and should restart.
Edit: this is why the developers are focusing on fixing problems within the game engine, and quest fixes are coming later. This way, any broken quests that are in fact caused by corruption, will be gone, and any bugs that remain are valid scripting bugs with quests, which can be easily fixed. At the moment, with the game engine causing corruption, it is difficult to know whether a broken quest is caused by a scripting error, or whether it is caused by corruption.