Things I'm not in favor of,,,,,, Since you asked. Here's a short list.
Priests being able to forgive sins. The Pope as the Vicar of Christ rather than just the head of the earthly governing body of a denomination. Forbiding priests and nuns to marry. The Rosary,,,, IE praying to Mary or any saints. Relics. Pennance for sins. Belief in Purgatory, Paying to get a shorter time in purgatory. Infant baptism. Everything about communion.
The absolute number one thing I believe the Catholic church should change is,,,,,,,,
The belief that only Priests are able to interpret, teach, and explain the Bible.