Summoning Carbuncle probably isn't the biggest accomplishment, which is why the Arcanist Storyline doesn't really acknowledge it.
Going into the lower levels of the Arcanist guild shows that the Carbuncles actually need some level of training to be useful. So... it's probably just a 'congratulations, you can do what your fellow Arcanists can do. Now make it capable of walking a straight line with out falling over.'
As much as I love Carbuncle, I think the lack of 'connection' is intended, so we don't feel bad when we lose access to the little ball of neon fluff.
Going into the lower levels of the Arcanist guild shows that the Carbuncles actually need some level of training to be useful. So... it's probably just a 'congratulations, you can do what your fellow Arcanists can do. Now make it capable of walking a straight line with out falling over.'
As much as I love Carbuncle, I think the lack of 'connection' is intended, so we don't feel bad when we lose access to the little ball of neon fluff.