just a idea to simplified usage

you can create form type guesser Symfony\Component\Form\FormTypeGuesserInterface based on your annotations like i did in my bundle

https://github.com/S0RIEN/DataGridBundle/blob/1a9ef2123d073df5749a88d646d1d3edbfb0b892/Form/GridTypeGuesser.php

greetings,
Sorien