One aspect I use to LOVE is customizing companions, and more specifically HK-51!! I would actively seek out the latest armorings and mod schematics to gear out HK-51. Back in the day, you could earn the specific droid parts for HK... BUT if you wanted to go the extra mile, you could gear him using the orange droid components and player made armorings. My guildies would have companions duel where we would test out various 'builds' on different companions... we'd be decked out in presence-heavy gear and have duels on the guild ships for S&G. It was a level of customization that got taken away and would be great if re-instituted.