I'll offer my experience from going out as Kylo.
First off, yes, there are options for brighter blades and louder sound. Sadly, it won't be enough.
Sunlight will still wash out the brightest blade. Crowds will still drown out the loudest speaker. You need to go beyond hilt internals.
Best display would honestly be a red polycarbonate day-blade. SF offers a thick-wall, pointed-tip red day blade, but Vader would probably be more accurate with a rounded tip, and you'll appreciate the lighter weight and brighter light of a thin-wall blade. But to make such a blade light up, you'll need to rework the LED system your saber uses.
String blades offer the brightest solution, at the expense of durability. That said, they should hold up fine for trooping, as your current experience with the ForceFX shows. A properly built string blade would be much brighter than your current ForceFX blade, but would require heavy modification or replacement of the stock soundboard. Depending on setup, an LED string blade may or may not retain the current extension/retraction effect. Can be assembled to be removable, similar to the FX blade.
In-hilt LEDs offer greatest durability, and while not as bright as a professionally-assembled string blade, will still be brighter than a stock ForceFX setup. Blade is easily removable since it holds no electronics - held in place by the emitter thumbscrew. In a pinch, a bladeholder for the Vader hilt can be fashioned from a piece of 1" SCH40 pipe, but TCSS sells an aluminum conversion kit that is a purpose-built solution.
Your board and AA battery pack can support a single-Cree easily for a slight increase in brightness. For maximum brightness with a Tri-Cree star, you'd need to modify/replace the soundboard and replace/modify the battery holder to accept an 18500 or 18650 lithium-ion cell.
Sound is still an issue. Hobby boards like Petit Crouton, Crystal Focus, Spark, Spark Color, and Igniter will provide a much louder saber, but it still won't be enough to extend sound more than a couple of feet, and it still won't compete with a croud.
My solution was to install an audio jack hooked into the speaker wires. This lets me run an audio wire into one of the Aker amps I use for Kylo's voice changer. This will be very loud, louder than the mic input, so I need a separate volume control wired to the saber to prevent blowing out the amp. This makes saber effects loud enough to be heard across a convention hall.