So how much does a design need to be changed...

It's hard to say with letters and fonts. Those 2 are very similar. If they were done by 2 people who never saw the other's design I would say they are different enough because 2 people can have the same idea.

But in this case if the current designer is concerned about being copied herself, and wasn't the original designer but was familiar with and used the original designer's work, then I would say credit might be due.

Now I may not be the best judge because I have felt for almost 2 decades that scrapbook 'designers' copy each other all the time and who knows what came first. I recall VERY early on specializing in heritage work, and I routinely scanned items and used them on the page. I submitted the idea several times and it was picked up by Memory Makers but CK had someone else submit the same idea and gave credit for the idea to that person. Was I the first person to copy an item and use it in a scrapbook? No, probably not. But I was the first person I knew to scan my wedding dress bodice and use it as background paper. So I was irked when CK got all excited about the idea from someone else more than a year after I sent it to them. Was it intentional? No, I don't think so because at that time everyone was on the get published bandwagon and almost any new idea could get your layout in a publication.

The new paper releases I see posted on this board - I could pull nearly exact papers from my stash or albums because they have been done before, not just once. I am cynical enough to say there are really only one or two undiscovered scrapbook page ideas and at least 5 people will think of those things at the same time.

I do see the resemblance. It might not be Birdgate level, but it's there.

First off, I do not support piracy or stealing artists ideas.

But, I think today's techno savvy society, it's becoming easier and easier to get away with this stuff. If Marc jacobs can do it, anyone can.

http://instagram.com/p/BcvQWrulBcX

It's pretty sad that we artists have to guard our work so heavily.

They are similar but my gut feel is that there's enough of a difference. I prefer the non-Paige one.

In fact, isn't that first one the actual non-Paige design? It comes from this fashion tattoo place.

I had never heard of this until your post. I looked up the designs and it is CRAZY - the MJ designers didn't even try to disguise their blatant theft at all. 
I hope that the small businesses that were plagiarized can win their lawsuit.

No idea about this situation with Paige Evans but to avoid being sued by a company or person, there needs to be 7 points of difference.