I'm pretty much of the same mind as Brent... that is, the more I take caddies, the less inclined I am to seek them out. Part of it is because I am inherently cheap and just don't want to pay for the luxury... but part of it also is I too have been a caddie earlier in life, and so knowing what I know... well... it makes me tend to enjoy their services less than I might.
By that I mean I get annoyed more than I should by deficiencies.
Luckily this hasn't happened often. I'd say 95% of my caddie experiences have been great. In fact, not to beat a dead CPC horse, but the caddie I had for my round with my Dad there absolutely MADE the day for us.. couldn't have been better getting my Dad around and treating him like a pro for a day, and a friend. So hell yes caddies can be and usually are a great positive.
But this all digresses from the real question here, which is how might they effect one's appreciation of architecture?
And on that, I really think it depends on what one wants to know, and experience. If you are in it for the study, seems to me a knowledgeable caddie would only help. He's not gonna tell you things about the history or the like that you don't know already (if you are a student), but he IS gonna tell you things about how the course PLAYS that will be way beyond you as a visitor. And how could that be anything but a positive?