Binotto said there was much for Ferrari, who brought upgrades to the first round of the traditional European season, to learn.
"We are disappointed for the race, disappointed for the performance in the weekend. Our hope was to deliver more," he added.
"We brought some upgrades, aero and engine, and were expecting somehow to be in the fight, but it has not been the case.
"I think power-wise, straight line speed, we are good enough but certainly we have some weaknesses on the car that were highlighted this weekend. It's up to us try to understand and assess and to improve in the future."
Vettel, a four-times world champion, finished fourth with Leclerc fifth.
Ferrari are losing a lot of time in the corners, which does not bode well for the next round in tight and twisty Monaco, and are also finding the new Pirelli tyres tricky to manage.
Vettel damaged his on the opening lap and both drivers also lost time in the pits with a wheel nut cross-threading problem.
Binotto said the limitations seen on Sunday were also evident in the earlier races and was unable to offer a time frame for a solution.
"(The) more important (thing) for us is first to understand really how to address them and then I'm pretty sure we can do it quickly," he said. "We still believe development will be a key factor in the season."