A digital stopwatch is entirely different because it doesn't speed up as the square of time elapsed. Please tell me you understand that part.
I would actually be ok with a wizard stopping in the last 5 feet of a 20 or 30 foot fall, except that I wouldn't want to worry about exceptions. (Which makes me realize, maybe, what the trap is 5ekme or whatever his handle is was trying to set.) At that height you're not going that fast at the bottom. But of course at that height you don't need to get fancy anyway.
It's the big falls, where you're going really fast at the end, where I'm skeptical.
Although the player at the table says something like, "I cast the spell when I am 30 feet from the ground", what the
character in the game world is doing is using his visuo-spatial awareness while watching the ground come closer and closer and making sure he utters the Verbal component (now!) before he splats. The ground is not unexpected!
Again, falls not falling. But that aside, I agree there is no roll required to time it perfectly: you get to cast it when you fall without having to roll to see if you're so startled you forget to do it, or become tongue-tied from terror, etc. You automatically succeed. However there is nothing in there that says you get to decide where in the fall it happens.
Apart from the entire game system which lets you do what you are able to do when you want to do it.
Player: I move 30 feet and attack the orc.
DM: Wait, I'm going to roll to see if you attack the orc
before you move.
Player: WTF?
No. Completely false. There is nowhere in the rules that say they occur "when you say they do". It says they occur in response to something else happening. And every single other example in the game is a very discrete something. No other case that I know of (as I pointed out above to 5ekme) occurs over a time continuum in which the "reactor" gets to makes a decision, with mechanical consequences, about exactly when it occurs.
Counterspell. Imagine a caster in the process of casting a spell with a casting time of 1 minute. You are able to cast
counterspell when its trigger occurs, which is, "when you see a creature within 60 feet of you casting a spell". Tactically, if the caster wasn't casting that ritual then he would be casting nasty spells against you and your mates. If you
counterspell his ritual as soon as you can then he will subject you to 9 rounds of nasty spells. If you spend 8 rounds casting your own spells against his allies and wait until round 9 to
counterspell his ritual then you have saved yourself a load of hurt. This is because you timed your response to the trigger intelligently.
And it is just an intelligent use of
feather fall to cast it within the last 60 feet if you can see the ground. It's not cheating or twisting the rules or deliberately mis-interpreting the trigger. I am falling, I am still falling, okay, I cast it....now!
I really will reconsider all of this if you can point me to one.
Well, that's commendable, especially on the Internet.
I look forward to your reconsideration in light of
counterspell's trigger very definitely
not being a discrete, instantaneous event.
Again, if you think your version is "playing by the rules", find another example where a player gets to choose when a reaction takes place in a way that has mechanical impact (no double-entendre intended).
Again,
counterspell. Done and done.