The easy thing is to blame the Realtor. They may be partly to blame, true, however Realtors don't sell homes, homes sell homes.
Like another post asked, how many homes, like yours, have sold in the last 17 months?:
Compare the sold homes to yours. Buyers are looking for value. Homes that they perceive to have the most value sell FIRST. The rest are left on the market.
IMHO, 17 months means that your price is too high...it may be that the Realtor either doesn't know how to tell you, or is unaware. EVERY home will sell for the right price. What feedback have you received from showing agents?
The three things that determine if a home sells that you can control are;
Staging and condition
As far as the damage goes, when you notice it, do you report it to your agent? He/she knows who is showing the house and can get in touch with that agent to find out exactly what happened. Sometimes if an agent's clients have children it can be difficult to keep an eye on everyone in the house at the same time. One way around this is to have your agent escort all showings, but that is not usually possible 100% of the time. You certainly cannot hold your agent responsible for the actions of other agents and/or their clients.
Before you change agents, consider talking to yours about the issues that concern you. Your question here is a bit vague. Try to provide us with some additional as to your reasons for wanting to change. I've given you plenty of questions to consider.