This version of Emperor Palpatine is a reissue of sw210 and appears in set 8096, Emperor Palpatine's Shuttle. Prior to this set this particular version of Palpatine appeared in set 10188, The Death Star. There have been a long line of various Palpatine minifigures throughout the LEGO Star Wars time line.
Minifigure Parts and Accessories
This minifigure has five parts in total: the cowl, a cape, head, torso, and legs. Nothing new here, what you got with The Death Star remains intact.
Palpatine's accessory is a standard red lightsaber.
Army Building Potential
I'm going to call this a "low" ABP. Although the cowl, head, and torso, would have custom potential, there are less expensive ways to obtain them or suitable replacements. Need a zombie head? The Collectible Minifigure Zombie has you covered. Martial arts gi? Again, the Collectible Minifigure Ninja gets you there. That cool cowl? I see 21 minifigures with this part in BrickLink alone.
Honestly, you can now pick up this version of Emperor Palpatine in a set that doesn't cost nearly $400 USD. I'm willing to bet, however, there's a magnet set in the future that will make you kick yourself for buying this set to grab him.
(Pictures from Eurobricks)