I don't quite understand Springjack Shepherd in this deck. I think Celestial Ancient would do well in its place. I also think that you need to put in more Yavimaya Enchantress and more green mana to use her more consistently and allow for more good enchantments, such as Ancestral Mask and Sterling Grove if you want to make it legacy rather than modern.
I would also suggest Ethereal Armor . :3
Sorry to double post, but Sphere of Safety also offers awesome protection.
Thanks for the feedback, though i wish it to remain modern rather than to enter legacy. The reason behind Springjack Shepherd was to have some tokens to outnumber the opponent defenses or to have blockers in case i'm being pressured. Having Celestial Ancient would do me good if it can keep it alive, but one point it has the same dissadvantage of having Sigil of the Empty Throne, a five cost mana that also needs more enchantments to be of use. Though of course a creature is easier to deal with than a enchantment.
Ethereal Armor and Sphere of Safety seems to be great aditions, i haven't check them out because i didn't take into account the return to ravnica block yet, but i'll be sure to update it as soon as i can. Thanks again for the feedback.