Since an updated legacy system will no doubt show the light of day in the future, new legacy unlocks would make such an update awesome in a way. This thread will be for suggestions and hopefully BioWare will take note of these.
My suggestion: Since players can use powers restricted to a certain class via the legacy system, why not use weapons as well? This is has been mentioned before but in threads almost years old and I would like to refine such a suggestion.
Since abilities are only usable when heroic moment is activated, the use of class specific weapons e.g lightsabers, should be put in a separate function since a short burst to equip a lightsaber would be tedious. A separate function such as some sort of weapon type unlock would make for a much better approach, however seeing a group of smugglers/bounty hunters using lightsabers wouldn't fit at all, it would be much more wise to put a cooldown on these weapon uses.
For example; Equipping class restricted weapons lasts a couple of hours and won't be useable until in another 12-16 hours, giving these weapon uses sensible utility rather than a hole in a class's structure. This legacy unlock would be advanced class dependent and only unlock-able around level 20, an option to paying credits and or cartel coins should be optional and ONLY optional, like species unlocks. The abilities used with these weapons should already be attained and replace the existing abilities on the action bar until the timer runs out, which then the former abilities would come back onto the action bar.
If you agree with my suggestion, I welcome your compliments and constructive criticism, if you have any other suggestions post them and let this thread grow in valuable ideas. Thank you.