Too much railroad and telegraphic line graphic shown over and over?

I would say ALL the cgi graphics were overused, especially towards the end of the series. The final two episodes were nearly unwatchable, as they regurgitated prior details and graphics in an attempt to tie it all together (incorrectly, but that's a discussion in another thread).

It seems that the overuse of graphics was due to a lack of content. The first instance or two might have been relevant, but afterwards it's filler. I really didn't need to see the Civil War miniball animation thirty times!

Yes, it was up there for a long time. The underwater shot of the ship with barnacles was used quite a few times also.