Is it considered an transgression in supplication to ask for the full reward, multiplied 700 times, for missed prayers performed by the worshiper without presence of heart?

The prayer of one who prays without full presence of heart is valid, and he is not commanded to repeat it. However, his reward is commensurate with the presence of his heart in it. If he asks Allah to overlook his shortcomings and grant him a greater reward, there is no harm in that. For Allah’s bounty is vast, and it is not impossible, given the breadth of His mercy, for Him to reward a small deed with a great reward, especially for one who strives against his soul to attain complete humility.