In my humble opinion I don't think any type of correction is happening now. If for the last 10 years you can say that nobody ever came in and asked you to drop your rental price then you should consider yourself very lucky. I can tell you in the New York market at least one person every time I have a rental come up will try and negotiate the price with me. I always tell them I can't do anything for them and I move on to the next renter who can afford the rent I want.
I agree with what everyone has been saying about the Zillow zestimate. I've found that number to be spot on at times, but also way off at times.
Also, when you do comps in your area make sure they are really comparable to what you have for. For example, I recently saw a 3/1 house in my area rent for $2100. I would never get anything less than $2700 for a 3/1, but my rentals are always in excellent condition and rent very quickly. All the counter tops are granite, cabinets either are new or have been replaced in the last 5 years, bathrooms are fully updated, etc. I want what the market offers, but I also put out a product that the market wants. The landlord in my area put out a product that should only get $2100 rent. I would never let another landlord's inability to keep up with his rental effect how I keep and market my rentals and you shouldn't either. Good Luck! :)