I saw those last night via the "Omni Viewer" on YouTube. Assuming these figures will closely match the final onscreen designs (which SH Monster Arts is noted for), I'm pleasantly surprised how "traditional" the element are for Rodan and King Ghidorah. Omni noted how the new Monster-verse Rodan" leans how to his 50s design with the spade shaped tail and "suggestion" (because the photos don't clearly reveal the underside) of belly spikes. Ghidorah's forward leaning posture makes Omni Viewer wonder if the Kaiju will occasionally walk on all fours, like a bat. Well, the figure reveals an upper limb structure supporting the membranes much like a bat's, so who knows.
The biggest change is Mothra, particularly the head, body and limbs. The wings and their coloration seem very similar to the Toho designs, which the first thing a "regular" audience will notice. Omni described the head, body and legs as almost "wasp"-like with forelimbs a bit like a praying mantis. Some will say this is sacrilege, but I like this design. Now she is both beautiful (because of the colorful wings) and terrifying. I'd think even Ghidorah would give pause before attacking her. Omni Viewer appreciated the changes too and stated his opinions more eloquently than I could.
Godzilla himself is still closely resembles his 2014 design with a couple of subtle tweaks hearkening to the Toho concepts. You'll see the dorsal fins no longer look like a craggy, Bonstellian mountain range. Instead, they have the almost maple leaf-like structure the Showa and Heisei era suits had. Yay! The toe claws are more longer, more like talons. The feet themselves are still elephantine, but the "talons" counterbalance that. Someone also noticed the tail seems a bit more rounded at the tip, less sharp than the 2014 design. Personally, I like they've hit almost the near perfect balance between Legendary's own concept with subtle flourishes of iconic Toho details.
In short, if these toys truly reflect the designs we'll see in the movie, then I'm a very happy camper!