You still think timed grenades are random? Let's compare the two grenade types: Let's say I rush in Arctic and toss a grenade over the barrels...
Your logic is flawed in using Arctic as an example.
Here's my stance on grenades. They're GRENADES. They're designed for taking out LARGE GROUPS OF PEOPLE. That's why you can only hold ONE. Timed grenades are so ineffective that they only eliminate maybe 1 person for every 10 grenades thrown, and half the time those are direct hits. If you want direct hits, you can just shoot people -- considerably more effective!
If the Quake2 physics weren't so fast, they'd be pretty effective, but the way it is now, the only way
to get hit by a grenade is to either stand around in one spot for a long time, be completely oblivious to an incoming grenade, and/or run into an area where a grenade is already sitting. These seem more like lack of skill or bad luck on the part of the opponent than skill on the part of the thrower.
I think calling impact grenades cheap is like calling the paintball markers cheap because it only takes 1 shot to kill someone. If someone throws a grenade at your feet and he's standing right in front of you, it's your own fault for not shooting him first! I mean, he's standing right in front of you; it only takes one shot!
So the way I see it:
Impact grenades: Powerful weapon for taking out groups of opposing forces.
Timed grenades: mostly useless; depend entirely on luck.
I also think grenade ffire should always be on -- people won't throw grenades at their feet if they keep eliminating themselves.
Another thing to think about: newbies. I think a lot of people dislike impact grenades because they don't like being eliminated by newbies. I'd like for this community to grow, and the only way to do that is through more newbies. If it's impossible for them to get any kills, they probably won't want to keep playing.
On the subject of priming grenades, my idea is like this:
+tossgren starts the priming
-tossgren throws the grenade.
So you'd do something like, "bind g +tossgren" and pressing G would start the prime, releasing it throws it.
Another possibility would be to make it so you have to switch to the grenade to use it -- like the hand grenades in Quake2. I think impact grenades would be more justified then, since you couldn't just throw them at the ground in the middle of a fire fight.