This may be a market specific issue, but in California the boiler plate forms (CAR Residential Purchase Agreement paragraph 11) will have an "as-is" clause built right in to the contract. "Unless otherwise agreed in writing: (i) the Property is sold (a) AS-IS in its present physical condition as of the date of acceptance and (b) subject to buyers investigation rights". 'Subject to buyer's investigation rights' is the key phrase in this case as those terms may be subject to further specification in the contract.
The way I explain this to my clients is that all "as-is" means is that the seller is not obligated to make any changes to the property, however it does not mean that we can't ask them to. Of course, the seller has the right to choose whether or not they would like to accept the offer based on the terms specified in the contract. However, if you have an inspection contingency in place, and inspections reveal a material fact that was previously unknown to the buyer, they have every right to issue a request for repair. At that point, the seller could choose to simply reject the request, in which case the buyer may or may not choose to exercise their right of cancellation of the agreement or simply proceed as previously agreed and eventually remove their contingency. The seller in this case is under no obligation to complete the work but they may opt to do so if it means preventing the transaction from falling through or even simply in a show of good faith as some sellers may very well choose to do, particularly if they themselves were unaware of the issue and understand that it affects the desirability of the property. Alternatively, the buyer may simply choose to ask for a price reduction in light of the discovery. In either case, so long as the contingency is in place, they have every right to attempt to renegotiate the terms of the agreement. I hope this helped!
