I think if you really enjoy TWD, you should keep it, and let try to get your 7yr old comfortable with it. My kids are 4 and 2 and couldn't care less about my TWD machine. I think part of it is trying to get them to let go of that fear of ugly things (will probably help them in several aspects of adult life) and get them to focus on what it actually is (a fun and challenging pinball machine).

OR, you could always take down or cover up the translite, then there won't be anything to look at, but that's kind of counterproductive to my suggestion above. Either way, GL! (and sell that pool table, it's taking up precious pin space! )