There is a new plastic kit coming for Tyranids, which are due to be the next big codex release for Warhammer 40k. Whether other kits will follow this one and go from Finecast Resin models to plastic kits, is still to be seen, but at least we have some information on this one.
Please remember that these are rumors. This is very solid btw, and I would consider this one as true as any rumor can be.
via an anonymous source on Faeit 212
New Plastic Hive Guard: Not a dual kit with Tyrant guard - the box just contains 3 hive guard
There is another ranged weapon option for Hive Guard that looks like a spike with 3 talons on the end of it.