Don't you think that a God who can hear from heaven could also see from heaven?
2 Chronicles 7:14 KJV — If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land.
And He can certainly see from heaven enough to know if men anywhere seek God:
Psalm 53:2 KJV — God looked down from heaven upon the children of men, to see if there were any that did understand, that did seek God.
I don't disagree with you in this sense, that He wanted to experience the wickedness in some way. What I've suggested is that He was giving them a chance to repent by sending His angels (not going Himself, necessarily, since it was angels Lot seemed to deal with) to test the people of Sodom.
And if only angels, how is that different from how He previously received the information about Sodom's wickedness?