Join Date: Nov 2012
Location: Beyond the Pale
I have a similar collection from the old 3ed days that I am going to pull out and play (although triple most of the swarm bugs). The new codex "feels" to me like that way tyranids should be played. Hordes of small bugs backed by the larger and specialist bugs. So if you have the money to buy the codex and like the models (nids are a great line) then go for it. It is always nice to have a second army lying around.
I can make a decently playable list with what I have, but like what you posted above I need some of the MC bugs to round it out and a few more of the mid sized bugs like thropes. It would also be good for you to expand the gant hordes, because numbers are one of the nid advantages. Just doing a point look-over that is about 650 points without any upgrades. So a few zoanthropes, some more gants (take the termi horde to at least 20), and one or two monstrous critters would get you to a 1000pt list easily. You would have a decent number of synapse for that point level and it would be a playable army that you could use. Play some games with it and then you can figure out where to expand.