Would it be possible to "lock" your abyssite with the NPC Assai Nybaem in Ru'Lude? You designed them to upgrade with the idea of people actually killing the bosses - but majority of the time this is just a detrimental side effect of doing Trials of the Magian. I wouldn't mind you making it so that nothing could drop from the VNMs spawned while under this effect.
I just find it annoying to have to either get a T2 on an alternate account and log/warp them before it dies so the abyssite doesn't upgrade, or the other annoying method of just getting a T3 pop and then getting another T2.
It's nothing major. But not everyone has access to alternate accounts. As it currently stands its actually detrimental to get a T2 abyssite with your own character for fear of it upgrading mid trial - you just have to hope your group has enough T2 abyssites to last all the mobs you need or for you to use a friends abyssite. (Either way its annoying)
Summary: Method of stopping T2/T3 Abyssite from upgrading when doing TOM.