Sorry to say, this is common when working with Captivate/big flash files. Depending on the LMS and the bandwidth, this may be quicker.
Captivate loads the entire file before playing, hence the long load times. Articulate loads each slide on demand so you would see better performance that way. Depending on the flash courses and how they were designed, they probably are loading on demand as well (thats the way I design mine).
Lectora courses load page by page, so it doesn't matter if you have 100 or 10000 pages, its a page level load. Keep that in mind. It is always a good thing to optimize images that you have on your pages. Reducing a file size from 150k to 50k does help speed up loading.
Note as well, Oracle's lms most often is running in a corporate envirionment. So you are also going to have extra overhead with security/firewalls network congestion that would wouldn't see on an external hosted environment (like coursemill). (actually it may be worse for internal corporate trying to access coursemill though because of security)
