Eric Musco explains in a Dev Post why they had to do some equipment removal for 4.0 from vendors
Customer support about equipment removal | 10.23.2015, 08:54 PM
For the question at hand about why equipment was removed from various vendors, this is due primarily to stat changes. With the release of Fallen Empire, we essentially made that gear obsolete due to the new stat configurations and formulas. This meant the best option was to remove those items. Obviously, this raises the main concern of the support call which is the appearances of those armor sets.
The dev team informs us that virtually all of the core armor appearances previously on those vendors can still be located throughout the game. The majority of the old armor sets can be found via Crafting rewards, Missions, and Heroic Mission rewards. Now, there may be some variants of these core armor sets which are no longer available, but we’ll adjust that over time and slowly re-add pieces. If there are specific armor sets that can no longer be found, send the information to the Community Team and we’ll pass it along.
Taking a bite out of the people who can help with getting you back into the game, helping you restore missing items or characters, and addressing any billing issues, really isn’t a good use of your time, or theirs. As a general note, if you guys have feedback or questions about design decisions or development philosophy, come to the forums and raise it here. Going to Customer Support is not the correct place for that (and we will ask CS agents to direct you appropriately).
Thank you all for your understanding and hope that clears up any confusion on the issue.