Have we found a good balance of risk & reward?Yes.
The changes to addiction have made it possible to experiment with different drugs. Through experimentation, I have been able to develop a mixture of chemicals that work well for my character. Because of the lower likelihood of addiction, I have even been able to branch out into other drugs.
While the 'other' drugs are not necessarily beneficial for my character's niche, it's get to be able to get a sense for why other characters might use them. And from that, extrapolate what other characters are focused on in their own development.
It is my perception that the current system encourages the use of chemicals. A player with zero knowledge of the chems can experiment with them and develop a solid understanding of their benefits and drawbacks.
As much as I hesitate to ruin a good thing, I am going to suggest that drugs might need to be SLIGHTLY more addictive. (With the emphasis on slightly.) Although my character has been using the same three to five drugs, once a day every 1-3 days, they are still not addicted. In my character's mind, they are dependent upon the drugs. By that I mean, they would not do anything "important" without being on at least one drug.
Are the experience scripts adding to RP? How could they be improved?
Yes they are adding to the RP.
Another round or two of scripts triggered further into the experience would improve my RP. I kind of default to being generically 'high' after a few minutes. By that I mean, I'm not so much roleplaying the effects of a specific drug as I am roleplaying being in an altered head space. To be honest, after taking 3-5 drugs at a time, I lose track of which effects are which.
My suggestion is a second round of experiences around minutes 3-7, and maybe a third or final round of experiences around minutes 5-13 or whatever.
I haven't obsessively tracked how long the drugs last. Though it seems like a while. "Long enough" is accurate. Long enough to need reminders feels right to me.
Are people using recreational as well as combat drugs?
90-95% of my character's drug usage is with recreational drugs.
If combat drugs have different addiction rates than recreational, then please take that into consideration with what I said for addiction. I just want to reiterate that I think addiction is very close to being right. A very slight tweak towards being slightly more addictive would likely be "perfect".
Suggested Improvements / Expansion of Drugs
Bonuses / Penalties
This should probably go on Ideas, but it fits here also.
A Bonus that makes Drugs slightly better and a corresponding Penalty that makes the more risky would be cool.
The Perk might be that they last longer. Twice as long. 50% as long. Whatever is high enough to make it worth spending 1 of 3 Perk points on it, but not so powerful as to be imbalancing. I suggest duration of drug effect instead of increase of drug effects (i.e. more Stat bonus) because duration seems less likely to imbalance the game.
The Penalty might be that a character is more likely to become addicted. In my mind, that would need to be almost guaranteed addiction after just a couple of uses. Otherwise it's not really a Penalty like other Penalties that apply to every single skill check that falls under the category of the Penalty.