I don't think it would be obvious to the newcomer that direct damage is suboptimal, simply because they don't have any other yardstick to base it off, and that the most (seemingly) rational means of stopping foes in their tracks would be to reduce their hp to 0 ASAP (basically tri-hero nuke + focus fire concept from WC3).
Speaking off personal experience, my first few spellcasters were all blaster-oriented. My rationale was that everyone in the party revolves around doing damage, so it seemed natural for me to chip in this aspect wherever possible. Initiating battle with a fireball, then have the delayed initiative fighter charge in with great cleave while the rogue sneaks attack from the side looked like a rather efficient mode of doing battle. It didn't help that many FR novels and PC games seemed to advocate this sort of fighting method.
It was only until the dnd forums started extolling the benefits of battlefield control spells that my players started taking a serious second look at them and realizing their latent power, just waiting to be broken...
Likewise, while one can certainly understand the effects of debuffing spells like glitterdust and web, it is easy to underestimate their true potential. While I know what blinding the enemy will result in, I may not be immediately aware of the huge impact this have in actual gameplay, until I actually experience it for myself.
Then there is the "face" factor. When we sit around for meals after a long game, we will naturally start to joke and boast of our feats and conquests, and the most common (though not necessarily the best indicator) means of measuring one's contribution is by the amount of damage he did. It can get frustrating when you hear your friends bragging about his fighter dealing well over 500+ points of damage over the course of the adventure, while your wizard's best accomplishment is blinding the horde of orc barbarians attacking you, much less convincing them of the extent and significance of your accomplishments. Never mind that it was probably your contribution that turned what would likely have been a TPK into a possible victory for the whole party.
That and you can't deny the thrill that comes with toasting the enemies with a well placed sculpted fireball...
I too think there is enough room between points 1 and 2 for a new label. Something where players actually make an attempt to build decent characters, but are hampered by a lack of guidance and overwhelming options and "tricked" into making suboptimal build decisions which look good on paper and in concept, but fall apart in actual gameplay. They have the right mindset at least (that you don't have to suck deliberately to be able to roleplay well), and can be educated.
It is a lot like M:TG in that aspect, when swords to plowshares and juzam djinns were shunned, while healing salve was popular because it granted life.