Besides a warming of relations with Beijing, the FTA will also open doors to similar agreements with other countries, notably Asean members. The United States will want to ink one as well, knowing that Beijing won't protest since it signed one with Taipei first. If I was an American government official, I'd certainly want to get it done within a couple of years to maintain (if not increase) trade and hence American influence in Taiwan. Why do you ask?
Quite simply the China-Taiwan FTA will either maintain or increase Taiwan's dependency on Chinese trade, potentially providing Beijing with additional leverage over the island. The United States may not yet be ready for Taiwan to assume a closer orbit around the mainland, therefore having an FTA with Taipei would at the very least maintain the status quo.
Is that a good policy? Depends on who you ask. However the U.S. government will find it increasingly difficult over time to maintain the status quo, especially considering China's military modernization. The U.S. would be hard pressed to sell F-18s or nuclear submarines to the island, which are fast becoming the most basic armaments in the U.S. military. Economically, China is likely to maintain annual GDP growth over 8% for the next several years and could easily show favoritism to Taiwanese companies in an effort to limit America's options.
I understand that kicking the can is always the preferable policy decision when confronting lose-lose scenarios. However I can't help but wonder if U.S. Taiwan policy will soon face a rather large wall.