Avoiding Deathtouch? (or touch spells in general?)

[Gnome]

I long ago house-ruled that Deathtouch and similar melee spells bypass both block and parry, partially reasoning the way other posters have (a weapon held in your hand is touching you quite directly), and partially to make melee spells like Deathtouch more attractive.

Despite this house rule, in many years of GURPS fantasy gaming no PC casters in my games have chosen melee spells. It's just too hard to pull off. You have to cast first and hold it (during which you cannot cast other spells), and then you have to hit with a melee attack, putting your squishy caster in front line danger, probably only to get your attack dodged by superior enemies that were designed to be destroyed by the skill 20+ weapon masters, not the wizard with Staff-14.

I've considered having melee spells trigger when the caster parries or is touched (like an Aura, but even more powerful as it arcs through weapons). I suspect PC wizards will still opt for buffs on the fighters, Blocking spells to avoid danger, and missile spells to do damage at a safer distance, as even this more powerful melee spell seems like an unnecessary risk (in the typical DF type game--obviously if those meatshields fighters aren't present, the calculus changes considerably!).