I have pierce train on a few of my pets and I would love that talent if it worked better but as it stands it needs work. When I see shield after shield being cast and pierce train isn't going off despite all of those casts being two/three shields at a time I have to question why pierce train doesn't work better than it does.
I think if someone casts a double or a triple shield pierce train should have a chance to break each individual shield off rather than a shot of breaking only one of them off which always happens to be the same school each time on the double or triple shield break. I thought that perhaps pierce train should knock off the entire double or triple shield at a time, but I think it would be a lot better if it had a chance of breaking off each one seperately.
In any case, pierce train should be made to work better than it currently does. Its a fun pet talent to have, but as is it seldom works.