The 2011 World Cup runners-up ended their campaign with a 23-16 home win against Scotland, which was not sufficient for them to avoid the first wooden spoon.
France lost three of their five matches and Saint Andre said the improvements his side showed were not reflected in the results.
"We dominated, we created opportunities but we lacked efficiency," Saint-Andre told a news conference.
"Once we get that efficiency, we could be a very nice team in 2015. And we have really improved during this tournament -- not in terms of results, obviously.
"During this championship, we have started to build something. We have very young centres (Mathieu Bastareaud and Wesley Fofana, 24 and 25 respectively), but also (wing turned fullback) Yoann Huget (25) who is coming of age at the highest level."
France, who lost to Italy, Wales and England and drew with Ireland, had to deal with injuries to three key players who started all three matches of Les Bleus's November series against Australia, Argentina and Samoa.
Fullback Brice Dulin was ruled out before the start of the Six Nations with a groin injury while flanker Fulgence Ouedraogo left the squad with an ankle problem after France's 16-6 defeat against Wales.
Captain Pascal Pape had to be replaced in the squad after the opening 23-18 defeat in Italy because of a back problem.
"It was not easy to make do with all these injuries," said Saint-Andre, adding he had less time to prepare his side than his rivals.
"While others run a 100 metres, we run a 110 metres hurdles.
"For the players' health, it would be good to pay attention to the number of games they play. It would also be good to have a proper summer break," Saint-Andre argued.
"Not four weeks as it is now, but maybe three weeks followed by a five-week period during which the players would work on their fitness and technique. Right now, they re-start after four weeks but directly with friendly games.
"Finally, we dream that we could have, like the five other nations, 13 days to prepare for the first match of the Six Nations."
Looming for France are three consecutive tests against world champions New Zealand at the end of an energy-sapping European season.
"It's the series of a lifetime," he said.
"I'm optimistic because we will go there with a 35-player squad, with players with great potential."
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