My advice in this scenario is role an alt. Perception on what is the most useful skill can change with an update or just over time - Cybertech was considered the worst skill of the lot shortly after launch.
Therefore don't waste the effort in gettin synthweaving to 400, make an alt, get him to 3 companions which doesn't require that much effort. With legacy providing a way of transfering things around characters it's easier to win an item on your main then dish out the components to alts for RE. Admittedly for mainhand/offhand this is more difficult.
This would be my advice too. Don't drop the skill. Make an alt. At the moment, Synthweaving (and Armomech) are in the same place regarding "end game" crafting. Just a few augments. But that could change
As the for the hilts/barrels, well, if you bought one of the legacy weapons from the last event, you can move around barrels. Here's hoping the next event will include a similar one to move the hilts