Nope, that isn’t it. Rather, in order to have interesting situational skills, you have to have skills of differential utility. You cannot ask for a system that is simultaneously homogenous between skills and also has oddball, quirkier skills which have niche uses.
Leaving aside strictly superior versions such as Fireball vs Firebolt - which still leaves open the question about whether everything should be AoE since that is the highest utility niche- turn to skills like Bone Wall, Time Warp, etc. and explain how these are supposed to be turned into equivalents to Fireball, Blizzard and Meteor.
And it isn’t just D2 either. It’s not like other ARPGs have solved this problem within a point-system framework, Torchlight has just as many issues. Oh look, it’s Exploding Shot, the skill that makes nearly every other damage skill look like trash. There are AoE knockback skills which work best with a single point. It also has the tedious “sink a point into this exciting passive skill!” stuff that D2 had going on.
The issue is you get access to all of them. That way you get to use them when the situation is appropriate. Exactly, dude! Don’t make me choose between getting Bone Wall and getting Fireball. Let me get both.
WoW solves this problem the same way. I like that my priest has Mind Control. If I had to choose between Mind Control and leveling up Mind Blast would I ever pick the former? Gimping myself for a fun skill is just not as cool as having access to both. Now I get to use Mind Control in the 1% of situations where it’s really cool (like Vortex Pinnacle, or doing Firelands achievements) while still having a non-gimpy Mind Blast.
Point is that well-designed skills (whether they be the direct damage stuff I’m focusing on now or the non-damage skills you mentioned) don’t necessarily have to suffer from “Skill A is always better than Skill B; therefore, do not waste points on A if you know about it.”
Did you even read what I wrote? The issue is not that A is always better than B; the issue is that A occupies a much more relevant niche than B. I’m going to quote that post.
It’s not even that some of these skills are useless- it’s that when you’re forced to choose, one occupies a much more relevant niche than the other (like Fireball vs Firebolt). When you AREN’T forced to choose, you can actually use niche spells when the situation arises, which leads to more diversity in the way your character plays. I’ve played D2 recently. It gets kind of tedious spamming the same 2 AoE skills for 80% of the game. I’ve also played Torchlight recently and it suffers from a similar problem. A tiny bit less so, thanks to the scrolls.
Saying that all skills must be interchangeable in utility is directly incompatible with a model where you have interesting niche skills.
This isn’t just Firebolt v Fireball either. I can put points into my Necromancer’s Revive- pretty much always goddamned relevant- or I can put it into Curse of Terror, which is a much more minor niche spell that is occasionally fun to use. Yet I like that a skill like Curse of Terror exists. I don’t want every skill to be a Revive.