Wrong Hamata for that Period.

What I see for Imperial Romans:

-Legionaries in Mail

-Legionaries/Auxillaries with Niederbieber Helmets 3rd Century (optiomal)

-Auxillary Archer in Western Style

-Auxillary Cavalry with Niederbieber Helmets 3rd Century (optional)

-Scorpion with Crew in Mail

-Late Roman Infantry with Spangenhelmets

-Late Roman Cavalry with Spangehelmets

-Scorpion with Late Crew

-Late Roman Commanders

As already said, Legionaries in Mail & Auxillary Archers in Western Style would be the most important.

No Antiquity, but for the Samurai ranges there are a few things that would really be good to see.

Early samurai:

Samurai on foot with naginata.

Followers with bows      
 

Sengoku range:

Ronin 

Peasants. We always need more peasants....

NIce would be some more Siege weapons like Gastapaetes and Onager.

With my next project being Punic Wars, could I second the above suggestion for Siege engines. This would include Battering Rams and Siege towers as well as the missle firing variety.

I stand corrected if wrong, but only think Irregular Miniatures makes them presently.

As Peter likes an indication of numbers for sales, I would commit to a couple of Rams, 4 Towers  8 stone throwers and 4 Dart projecting weapons.

Stay safe!

I've used a Magister Militum 10mm stone thrower has heavy artillery for my Romans. Looks OK even though I did glue the throwing arm on the wrong way up. And I've used some of the early Greek catapults as heavier bolt / light stone throwers more generically in a few armies.

I'm investigating options for other seige equipment, and apart from Irregulars haven't spotted anything yet and so might resort to to getting some 3d printed or scratch built

Thanks for the suggestions made David. I'll look them up.