Fiery:
I think you might be too focused on the parts of D2 that were wrong to really grasp what we’re saying about skills here. I don’t want to imply that I think you’re dumb or mean or covered in poop, just that you seem to be still hitting the same “But Diablo 2 had bad skills, so I don’t want to have to choose skills!” button.
Tower Defense games (the best ones, at least) often have a similar dynamic. You might have a “laser” or “sniper” tower that is phenomenal at 1-shotting any-Goddamn-thing. At the highest levels of play, it still takes down anybody who passes its way. . . but is best suited for single targets, since that’s all it hits. Then you will have a Cannon or Bomb tower that blasts high damage across an area. Great for mid-level mobs, but it’ll never take down a boss character. Slowing towers, freezing towers, high-DPS towers, etc.
Runes allow D3 to branch out even more from this. Maybe sacrifice attack speed or range on your high-damage, single-target spell to make it multi-shot; pay more mana to use it. Maybe up the damage of your AoE fireball, but lose some of the radius. Etc.
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.”
If someone wants to Bone Wall off a pack of enemies and plink 'em down with single shots from a high-damage spell, let them. If someone wants to charge into the group and unleash a frost nova to slow their attack speed and damage them all, have at. And if someone else wants to blast firebombs offscreen before they even see the enemies, why not?
D2 had bad skills (decidedly bad, actively useless, or later “replaced”). It made you stick with them, which was great from an ownership standpoint, but hurt from a gameplay perspective.
The point of all this is that an alternative to what Blizz has done in D3 would be to actually focus on making sure all skills could be useful. Yeah, you might have to think about how to do it (i.e., using Bone Wall or Slowing to let your high-damage, single-target work its magic), but that’s part of the charm (to me at least).
So, you’re right: some utility spells probably don’t need a lot of levels, or investment opportunities. That’s okay. Maybe Bone Wall or Hands of the Dead or whatever is “cheap” enough that anyone can grab it. Maybe it doesn’t even use or need Rune effects, although I say why not go ahead and use 'em. That still doesn’t seem like a reason to say that “all skills for everyone” is a requirement for D3 to be good/fun/balanced.