In the development area, at any time he has tried to offer full performance and efficiency in the fulfilling the task assigned, contributing with his point of view at potential improvements.
... I think you need to re-phrase this line... it does not convey your idea clearly. This is what I suggest, but may be I'm off track because I cannot grasp what you try to mean exactly;
He particularly displayed his great potential in the area of iOS development by meeting all the requirements effectively and efficiently while contributing valuable insights for future improvements.
P.D.: I forgot to remove the person name and de company name, could I remove this thread for privacity terms?
I removed those contents from your post :) Now no worries :D