There is a simpler way to avoid these problems. I don't craft in the laggy, busy areas. The market wards are one of my favorite places to craft because of the lack of players running through and no chat spam. The guilds are rarely crowded, and there are lots of places throughout each city that see very little traffic, in case you do want to be listening to the town shouts.

I'm not opposed to them adding some sort of indicator on the crafting synthesis bar to display the crystal color (perhaps treating it like the aggro meter) though.