Agree, plugins can't solve world hunger or anything, but using the term loosely, I do think they can do a lot to build enthusiasm for the game, as well as resolve many player frustrations, allowing Turbine to deprioritize those things and focus on new features/content.
I dream of being able to have my iPad up beside my monitor, tracking my quests/goals/deeds and plotting/following my course on a map, researching items and crafting recipes, managing alts, reviewing storage, etc., all without cluttering the UI. It would even keep me connected to the game when I'm not able to actually play. If I could show something that cool to friends/coworkers, I know we'd have more active players in very short order. Now, I'm not asking Turbine to create such an app, though that would be awesome if they did it right, but I would definitely be willing to sink way too much of my personal time into it if Turbine would only make it feasible, with well-supported, stable APIs, and I know I'm not alone in that.
*shrug* I'm a dreamer...the realities of business usually do nothing but frustrate me.
Seems like a good investment to me, but what do I know about Turbine's business model?