So with FW clearly streamlining their range i.e.
- Removing shoulder pads and replacing them with transfers (very cheap to produce, are very likely outsourced and don't require staff time to cast)
- The Mark IV box no longer has a unique box or Word Bearer transfers, just has generic ultramarines one stuck in (minor thing, but mark iv being perpetually out of stock suggests that they are doing runs of them)
- Removing the heavy weapons that don't have hands and aren't underslung
- Other kits being culled at the moment.
As a result, I don't think it's unrealistic to expect some plastic kits. Very limited amounts, but at least some. The one obvious thing here is that they're getting rid of the stuff that they have to cast and that they can achieve in cheaper ways. If I were FW and I wanted to get more profit out of heresy:
- Deimos Rhino in plastic, with supporting conversion parts available in resin. They already have the Sisters Deimos as a base, so use that and replace all the spare area with command tank bits etc. Then charge the same amount. Then, if they made plastic rhinos, it's a simple step to make a resin kit or a single plastic conversion kit for predators, whirlwinds etc. This gives them alot of mileage out of the kit.
- Assault or Breacher kits, with conversion parts for the unique legion units and destroyers etc. They would be cheaper than resin, unappealing for FW but they'd shift alot more of them.