But how many other 3e classes were created that were less engaging? 20? 30? Likely more. The odds of makings new, lasting addition to the game are likely 25:1. For every warlock, marshal, or ardent there's a healer, archivist, favoured soul, beguiler, hexblade, dragon shaman, dragonfire adept, spirit shaman, spell thief, and sooooo many more..
While I agree with your point that WOTC printed a lot of classes that were an unnecessary waste, the Spirit Shaman is a valid archetype worthy of its own class*. A Shaman class was found in the Basic D&D Gazeteers, the 2e supplement Shamans, and in one of the 4e PHB supplements. The 2e supplement aside as I have not seen it, the other official versions were, in my opinion, not nearly as well done as Green Ronin's class from its 3e Shaman's Handbook. Yet, the 4e Shaman was pretty popular (despite the need for a few more builds).
* I also think there should be both a Warrior Mage and Rogue Mage base class should exist. I just think the hexblade and beguiler were too specific. I would rather the spellsword, hexblade, eldritch knight, duskblade, and bladesinger all be subclasses of a warrior mage class that starts with cantrips and the arcane trickster and beguiler be subclasses of a Rogue Mage type base class that starts with cantrips.