It's an interesting design space that I do think is worth exploring, TBH (I wouldn't be spending so much time on it if I didn't think it was a cool idea to explore). I guess I'm just wary, given the current discussions on Rumor Mill, of big, powerful effects that just completely turn something off. I'm just worried about a spiral of a runner who can't play enough cards from hand and has draw effects they can't turn off being stuck in an endless run-less loop. Imagine having a hand full of run events (or just things you can't afford without some Temujin money), and the corp rezzes an Agroplex which, guess what, you now can't run to turn off until you draw enough non-run event cards that you can afford to play for you to get 2 of them out of your hand in one turn. The corp could IAA a naked 5/3 and the runner would be powerless to stop them from scoring without The Source in play. Admittedly, on the corp side, I can definitely see the appeal of that, but I think it's NPE territory for the runner.
As for activating it, I think you can't just look at corp actions here, but instead need to look at forced card draw and damageless hand size reduction as a whole. On the Corp side you have Agroplex (and, I guess, Aiki) for draw, but for hand size reduction you have Chairman Hiro, Enforced Curfew, Valley Grid, and Gyri Labyrinth. If you deal 3+ points of brain damage, you make it impossible for the Runner to draw up to survive a Snare! before running, which could make for some cool mind games but would also drag out a game by making the runner overly cautious.
On the Runner side, you could shut yourself out if Earthrise, Drug Dealer, and/or Safety First is important to your strategy. I guess the runner has a choice to not install those things against this ID, but some decks are dead in the water without that draw. It's also a massive first-turn hate card against Andy and Adam (assuming you need, and don't pack spares of, Safety First), especially since they usually rely on at least some run-based economy on that first turn. Adam might be happy about getting to ignore that first forced run from ABR, though.
Some thoughts on partial run prevention rather than complete shut-off:
- Exclude runs initiated from card abilities from the effect (allows run events and click-to-run installed cards).
- Flip that and only allow basic runs, turning off card ability runs and saving you from Siphon.
- Cannot run a particular server or servers (e.g., flip RP and prevent the runner from running, say, HQ if they're over their max hand size; but that's kind of anti-Criminal, and could cause issues with turning off one of the runner's main ways of dealing with asset spam).
- Deal damage (net or meat) when initiating a run with over maximum hand size, or make discarding a card at random an additional cost to initiate a run in such a case. The runner still gets to run, but it costs them potentially important cards.
- Reduce the number of cards a runner can access (from HQ/R&D, or from any server other than Archives), or prevent the runner from accessing more than 0 cards from a server (a la Eater), if they're over their maximum hand size. Still allows economy and special effect run events. Also makes Gyri Labyrinth and Valley Grid stronger, with the latter potentially defending itself to a problematic degree.
- Make the effect check at the start of the Runner's turn, so you can turn it on with Agroplex/Hiro/Curfew, but it doesn't prevent the runner from locking themselves out by overdrawing, except through Drug Dealer. This one still hurts Andy and Adam first turn, though.
I don't know; maybe those all have the same problems, or maybe it's a rarer case than I'm giving it credit for, and the Corp should be rewarded with turning off a run if they can pull it off.