There is always room for negotiating new construction whether it's for closing costs, upgrades etc. Remember that the sight agent represents the builder/developer. Ask any sales agent working for the builder and the answer you'll most likely get is that you don't need an agent I can take care of everything. This may be true but it doesn't get you personal representation that all buyers should expect and have. A good question to ask is "Who will represent me?"
Having a buyers agent that represents you personally is a huge benefit from negotiations to asking important questions. There are higher fees in the closing of new construction and it's important that your agent points them out to you.
Make sure that your agent accompanies you on EVERY first visit of new builder viewings. As the builders will not take kindly if you view their models and then come back with your agent. You may loose your agents representation if you decide to purchase from them.
Buying a new home is a business transaction first and foremost and you should have someone on your side to represent you and only you! Let Me Know When Your Ready!