Slow main menu, system maps, outfitting and starport services can be down to File I/O and Network.
The network traffic & load to the Servers, and there are many things which can affect this, can impact response while the game waits for the data from the Servers. A number of which are out of our control such as Network/ISP bandwidth and load - I noticed some items are slower when my family are at home streaming youtube, facebook, etc... to their phones.....
Also, the HDD in the Xbox isn't as fast as players have in their PC's, and while the game caches what it can, the first visit can be slow while everything is loaded - there have been improvements made to the File I/O in 2.3, which Beta players have noticed.