Comical this shit is. As with any place, you can control what you are getting out of it.
For the most part, the meats are left relatively unseasoned (the bland comments) so that it is palatable for ALL customers. Some customers, if you haven't noticed, get VERY pissy about things being too spicy. If you want it to not be bland, ask for an assortment of salsas, which I generally ask for Verde, Roja, and corn. Add hot sauce if you like to add more.
For me, my only complaint is there is not a smaller burrito option, but it's not a big deal. As for the health related aspects... if you're worried about it being bad for you, you know what you need to avoid.
As far as I am concerned, they grill their meats in an area visible to their diners. They cut in front of their diners. If a place is preparing my food where I can see it, I am generally not that concerned because they aren't hiding anything. Authentic Mexican places? See if they let you in the kitchen.
Is Chipotle the greatest place to eat ever? Nope. But by and large you know what you're getting when you order it, and their results are consistently good. That's what makes a place successful is consistent good results.
All the comments about it being bland... you have options on how to have your food prepared. I suppose you could go to Hu Hot and bitch about the same thing when you don't add any sauces to your food. I dunno why it is hard to figure out that an assembly line that takes your requests and implements them is in charge for how bland your food is. It's grilled meat folks... and cheese... and rice... and beans... and salsa... what are you expecting?