Currently using the imperial bastion armor set. what would you suggest?

Almost anything else. Imp Bastion is (stylistically) heavy armour, well suited for a Jugg (the name suggests an Immortal (tank) Jugg).

If you have the necessary Oricon reputation, I quite like Hallowed Gothic from the rep vendor on Oricon. Otherwise some of the Force Expert's sets from Synthweaving, Dark Augur, Armored Interrogator, Xoxaan's. For an interesting variation if you have the right dye module lying around, have a Miraluka wear the Visas Marr set dyed Black/Black.

But in the end, it's your character, so scan through armour sets in Collections, preview them, see what you like.

One last thing: don't ask my characters themselves for advice, or you're likely to get suggestions like "Subversive dyed white/white". That character is the Rattataki Yerka Kolar, called Darth Nox, who followed a three-year path from slave to member of the Dark Council, and she wears what she wants, and aint nobody gonna tell *her* what to wear. (She does also have Kreia dyed Black/Black(1), which looks suitably Dark-V.)

(1) She got the dye module free from one of the old Cantina Crates when I created her.