i totally agree that wrong diet or too many things in a diet are detrimental - you know all mae's problems stem from her being fed on exclusively banana chips and chin mix - i would not encourage anybody to feed either of these.
my healthy chins get different types of hay, nuggets and wooden chews, oats every so often. that's pretty much it. that's what mae gets at the moment (no oats though) but i know people have managed to even get the roots to reduce with diet of increased vit c, calcium and dried veg - i HAVE to try. it is possible for overgrown roots to get smaller (obviously once they're in ocular spaces/sinuses it's too late) - my vet always checks if mae's has got any smaller. and i agree, not many vets know a lot about chinchillas, but two of the vets at my surgery do and i'm pretty sure they've been looking into chin treatments a lot more in the past year or so, simply because i have six (not that many chins on the isle of man). they have done c-sections etc in the past.
disagreement is perfectly fine - if everybody agreed, the world would be a boring place and more importantly, things would never get improved - and i respect your opinion. but there's a difference in saying 'this is bad and will kill them' and 'i would not do that because i don't think it's a good idea based on my experience'
there's so much information out there and a large chunk is wrong. when my mother was visiting, she bought the chins this 'complementary feed' that contains dried herbs, hay pellets, rosehips, etc. it says on the packaging to give your chin a SPOONFUL a day and my mother was trying to convince me that that's what i'm supposed to give them! it took an hour of explaining and arguing (my mother always knows best, even when it comes to subjects she knows nothing about.. she's never had a chinchilla) - it drives me nuts because people who don't know better would follow the advice because you'd think they would not be allowed to sell it if it's not safe..