>>19986330I would make them bigger and heavier, letting them look more like actual "primal" forms of their type. Primal Regirock looks like walking mountain and primal Regice like a glacier, no idea for Registeel, though.
Regirock gets:
+50 Def
+25 At
+30 SDef
+15 SA
-20 Spe
Regice gets the same with special and physical stats reversed.
Registeel gets +40 in both Defenses and +20 in both attacks (and also -20 Spe).
They all get abilities that let them use moves of their type with their corresponding defense stat:
Regirock uses physical rock type moves with its Def instead of Attack and Regice uses special ice type moves with its SDef in stead of SA. Registeel uses both physical and special steel attacks with the corresponding defense.
Names could be something like "Walking Mountain" or "Walking Glacier".
