Re: The law is wrong
Changing the law in the way you suggest may have unintended consequences, e.g. making anyone who grabs a kitchen knife off their own kitchen counter defend themselves from a burglar a murderer, without any wiggle room to argue self defence.
We could easily allow being at home as a defence to the charge. If someones breaking into your home and you grab a knife, its not the same thing as walking the streets with one day in and day out in case you feel that you 'need' to stab someone with it.
The premeditation part is the taking the knife out of the house to walk the streets with it (exceptions already apply for camping, coutnryside activities). I certainly wouldn't take my camping knife to work - its rather large (and heavy), and I don't need a 9" blade to type with.