Player: I cast fireball centred right....there!
DM: That's....95 feet away from you.
Player: No problem; the spell's range is 150 feet and I have a clear line of sight.
DM: There's no way you could be so precise in the midst of combat. Roll a DC 10 Wis check to see if you manage to place the spell correctly.
Player: *rolls* Darn, 8.
DM: Okay...that means...you've killed the king and his entire family, who you were there to protect. Having fun yet?
There is no expectation in the rules to have to make rolls to have your spell casting decisions be the subject of skill checks. We don't have to roll to see if we place the blast radius in the right place, or to cast the spell when we want to cast it, or to affect the six correct targets with a friendly spell. These are automatic. If they weren't, D&D would've made this clear in the last 40+ years!
There is a difference between how the players experience this and how the characters experience it. For the players, it's things like, "I centre the blast radius 20 feet from the cave mouth", "I target all the party members except the wizard", "I cast the spell as soon as I get within 30 feet".
But the creatures in the game world are probably not doing that. They are more probably thinking things like, "I cast the spell....there!", "I buff these guys", "I cast the spell.....now!".
Feather fall should not be nerfed by an extra roll (or two rolls for you!) where failure could result in death, when there are no such rolls for the other spells. It's either all decision points of all spells, or we assume that the caster gets to freely choose these things without requiring rolls to see if he gets it right!
Which is it? Well, I think the game would mention it if rolls were required. The game allows creatures to do the things they can do whenever the rules allow them to do it. The use whatever action is required whenever the rules allow them to use that action, without randomly rolling to see if they got the timing right. They allow the spell to be cast at the desired spot within range, without randomising the distance. The caster attacks or affects the creatures he chooses, and concentrates on spells as long as he wants.
In fact, where things are uncertain, the rules are sure to tell us when! Do you hit your intended target? Yes. Yes you do. Unless the rules specify an attack roll or a saving throw. Do you keep concentrating on that spell? Yes, unless a concentration check is forced upon you as described in the rules. Do you aim the blast area where you intend? Yes. Do you cast the spell when you intend? Yes. If these things were subject to random rolls, the game would tell us.
Agree for the most part but let me add... this is not fireball... this is a reaction.
with other reactions i can make my decision to cast a spell or not AFTER i see the roll in some cases, after a beam of light is thrown my way etc.
No roll for timing required for those.
Changing to add chance of failure and risk to a spell that is IMX most often used to try and save PCs and allies is not a direction i would be taking for a spell used so rarely and with really no significant game imbalancing in play history.
But some folks see it differently, of course.