A big part of his intended role is his ability to keep surviving. While less speed would definitely discourage him from being a base-invading rambo, it'd also make it harder for him to pick his battles in the field. That might be a bit much in combination with no kovtillery, though a 5-10m range increase and a more viable ranged anti-infantry option could help with that. Also, every other expensive Soviet infantry is slow, Volkov is the only fast one besides Starshina and Grenadier. Maybe if his speed goes down, the Shock could go up to help him in his intended role - but how to justify that given how bulky his equipment looks? (Besides renaming him to "Shocky Gonzales")