Not a good idea. The trinket has to "charge" and it does not charge when it is on cd. So if it comes off cd and you immediately use it (which would happen if you did use WoG on cd), then you're probably only getting a heal for a few thousand.
---------- Post added 2011-09-14 at 06:19 PM ----------
Symbiotic Worm is very good until you're approaching CTC cap. The closer you get, the more useless it gets. For me, SW would only be stamina.
I use the alchemy trinket on most fights. It is a very good trinket. Next tier I'm sure I'll be dropping it.