NotebookLM has stopped feeling like NotebookLM, and I'm still deciding if that's a win

NotebookLM's original value proposition was grounding — letting users control exactly which sources the AI could draw from. Over time, features like Discover Sources, Deep Research, and now code execution have shifted that model: the AI now searches, selects, and synthesizes on its own. The author argues this feature creep undermines what made NotebookLM distinct, turning a focused research tool into a general-purpose AI assistant that has lost its identity.