Sforno on Numbers 11:15/ספורנו על במדבר י״א:ט״ו

1ואם ככה את עושה לי, If You in Your perfection decided not to provide me with assistants in order not to belittle me in the eyes of the people, and You want to continue to lead the people in the manner which You have done so far, הרגני נא הרוג אם מצאתי חן בעיניך, so that You will be free to appoint someone else, someone, or several, who are able to lead the people more perfectly. This is reminiscent of what the sages have said about the prophet Samuel who died before his time in order to enable the Kingdom of David to become reality sooner. (compare Tossaphot on Taanit 5)

2ואל אראה ברעתי, the result of my inadequacy as a leader. If I had to witness this, this would be worse for me than dying at this time.