I did not read everything, but ain’t an EMP an Electric Discharge? If so, with a sufficient power, you could disconnect cells causing either permanent or temporary damages in any organic part touched by the wave.
One thing that makes an EMP (If we stay in the grenades, if we just make a deployable, it could be as powerful as we want or at least as long as it has a good source to draw the electricity from.) less viable for a mind-altering gadget is that it would require a huge amount of electricity (If I recall, that’s what is used in the EMP’s), and providing such amount would require a grenade the size of a soccer ball. (And no it’s not easy to throw a soccer ball filled with materials to contain all that energy, not to talk about the possible stability-issue from such a high power stocked in such a tiny space.)
But it would be possible to achieve effect that would end up hurting the target in a permanent way or at least a temporary way enough to get it/him in a significant disadvantage.
Anyway.
As for the nanites, they are technically possible as well.
All you would pretty much need is a way to make a high quantity of them (Which is far from obtainable currently, even with the current science advancement.)
As for in tremulous, Nanites are entirely possible, and depending on how it is used, it could end up being used in both offensive and healing/defensive situations.
The thing is that it would also make the use of EMP and pretty much any other weapons not Nanite powered pretty useless as Nanites could be used to literally just destroy the connections between each cells of the body. (With enough nanites, it can take from a few minutes to a few dozen, concidering the limited amount you can have in a Nanite Grenade/Injector, it is highly improbable to have enough to cause instant death, so This would make this a overtime effect (Pretty much like the current poison) but would affect the maximum amount of health possibly. (Unless you allow friendly nanites from medistation to regenerate the damages.)
(After reading a little about edaq’s posts)
There is always a smaller distance (Considering that to have something visible, it MUST be made out of something. It cannot be completely empty. Personally I like to think that the whole universe is a big version of what we discover. So basically, it will be near impossible for the humans to ever discover the smallest distance or even the smallest particle
Anyway, all that wall just to say that Nanites would be a pretty nice idea in my opinion
and that it would fit tremulous a lot.
Even if Nanites can be OP, depending how we limit them, they can provide a great feature.
Just as a side-note for those who are not familiar with nanites:
(If I recall well, it has been a while since I read about nanites.)
They are basically little robots who does a specific action over and over and gets charged by different method (either by another nanite or in a charging station in the device they are sent from.) They can also be a one way use and die right after their action. (In this case they are mostly used for damaging a target. Tissues, Muscles, Brain and such are often a great target as they might cut some connections in between cells which might cause problems afterward.)
Ok… Time for me to stop writting… (I have been writting for 30 minutes already.)