Repeating the same lines over and over again is not necessarily bad, it can help you focus and meditate on one idea. The four living creatures in heaven don't rest day or night saying, "holy holy holy, Lord God Almighty, who was and is and is to come". This is in Revelation 4:8.I don't know about the praise and worship music in churches nowadays. They are either too focused on self or repeat the same line over and over again until you start thinking about something else. That's what goes on in my church.
Although, I do agree that praise and worship songs that focus too much on self are not good. After all it is God we are praising and worshipping, so the focus needs to be on Him.