I would love for there to be an option to train all our pets at once. This would save some time, as having to individually train each one seems rather tedious. If this idea is made real, it could lead to become to an awesome GA perk, or at the very least, people could add a bit more CSC to train their pets in this way. I hear this was suggested a long time ago, but it never really picked up, so I'm putting this out here again, in the hopes that the staff can give this a thought. :)
iirc this gets rejected because of the differences in training times. It wouldn't really affect me anyway so I don't mind if it gets added, if there's a workaround for that. [edit] I missed the autotrain part. Yeah sure, why not?
If this does get implemented, I hope it's like the Resort where all the pets have radio buttons and you can choose which ones to mass-train. I'd like the convenience of being able to put multiple pets into training at once, but I wouldn't want literally all of my pets in training at once. xD

Same as Keliora here. There are some pets that I do not want to train anymore for one reason or another (e.g. Heparin, who has a ridiculous level stat -- trying to raise their stats with the zapper is more economical at the moment,) so if this gets implemented I'd want to tick the ones I want to train rather than autotrain all of them at the same time!
This would be convenient, though even though I'm not a programmer I can see how there would be a lot of issues in getting it implemented (difference in training time and price of training, etc). But I too would want to be able to choose which pets to autotrain. Some of my pets just don't need training, or wouldn't need training in one particular stat.