The Santiago Bernabeu side were beaten by Atletico Madrid in the Copa del Rey final after Borussia Dortmund ended their Champions League dreams, while Barcelona proved to be too strong in La Liga.
"We cannot be pleased with how this season went in general," Modric was quoted as saying by Marca.
"A club like Real Madrid cannot afford to go trophy-less."
The 27-year-old midfielder then had his say on Jose Mourinho, who left Madrid for Chelsea this summer after three years at los Blancos.
"I can only speak well of Mourinho. He's a fantastic coach. It was a pleasure to work with him. He taught me how to play more aggressively.
"He always tries to get more than the best out of every player. If you give 100 per cent, he asks for 110%. If you don't play to the best of your ability, someone will come and take your place."
The 27-year-old went on to say that his best position is as a playmaker, having been used in a variety of roles during his first season in La Liga.
"I played in central midfield during my four years at Tottenham and I play there for Croatia," he said.
"It's where I feel most at home. I can organise and lead the team from there, like the conductor in an orchestra."
Finally, the Croatia star spoke highly of his Madrid team-mates, praising the work rate and commitment of the entire squad.
"It's amazing just how dedicated [Cristiano] Ronaldo is in training every day, how he prepares for games," he added.
"Then you see the quality of [Mesut] Ozil, Xabi Alonso, [Karim] Benzema... However, I wouldn't want to single any one player. It's an outstanding squad.