I was thinking that grenades having a x2 radius upgrade like c4 and I think rocket, would be awesome! Also it most likely won't work but having a diagonal pistol upgrade :)
In that thread you can post all your suggestions as far as weapons go.
Anyway, on to the subject, I don't think the 2x radius upgrade for grenade would be useful at all. It is already pretty easy to kill people using grenades, there's no need for any extra help as far as the radius goes.
And as for the pistol. The pistol is a cheap, simple to use, straight weapon. There's no need or want in my opinion for it to be diagonal.
Thanks for your suggestion but in my opinion, they are both not worth adding.