Neustadt suggests that for a president to be successful he must be also a successful politician. However, Eisenhower was considered to be a very successful president by many and viewed presidents as statesmen who float above any partisanship.
Neustadt believed that presidents accumulated power by making strategic decisions. However, by fact it's possible to say that this ins't true since they lose power after the honeymoon period.
Also, he suggested that presidency is not a place for outsiders who are not familiar with Washington. But, in reality, increasingly voters have elected outsiders. Many things have changed since Neustadt wrote his book.