Just for sake of discussion without accusation or alterior motives, all this is In My Opinion.
The Quran states that no man knows the day, and only Allah (SAW) may know it. Also any many who thinks he knows the day is wrong.
As for the argument by wil, it never says he wouldn't come and then leave and come back again. He had a job to do. And if Allah (SAW) had willed it, it would have been complete. Obviously there were more souls to test. (Islamic POV) Man was not ready for the Messianic Age that is fortold in the OT. There was much more that needed to be taught, but that wasn't the job of the Messiah. In Genesis, Allah (SAW) promises a great nation to Ismail (PBUH) and Isaac (PBUH). If Ismail (PBUH) or his descendants were not to play a big part why did Allah not tell Hagar(PBUHer) to just go, but rather he told her to return to Abram (PBUH) (later Abraham(PBUH)). The OT even mentions that Allah (SAW) spoke to Abraham (PBUH) about him.
Muhammed's (PBUH) job was not to deliver the prophecized (SP?) Messianic Age. He was sent to deliver the word of Allah (SAW) in its entirety. Parts had been brought before by several prophets, but they had degraded over time and some have been lost. Without this full message, the messianic Age would not work as prophecized due to the former messages only being sent to and applied to the Jews. (Jesus (PBUH) stated that his message is not for the gentiles but rather the lost sheep of Israel (Jews) yet the Messianic Age is prophecized to the world.
There are many reasons not to believe Jesus faced the Crucifixion, but that isn't the topic, so I will leave that alone. Also Buddha, why did you only mention 5 Prophets? There are thousands of prophets, over 100 we can get the names of. Some notables you did not mention: David, John, Solomon, Joseph, Adam, and Jonah (PBU them all). All of these are even mentioned directly in Quran.
The difference in the 2 quotes 26:24 and 26:53 is 53 is (literarily at least) Jesus speaking, whereas 24 is someone else (assumed Matthew).
Thanks for reading. Sorry for the length. Salaam Allahikum.