The real question is why would you call in a commander glider for an exactly identical MG team you have at tier 0. This isn't USF airborne where you are split by tech. Really the inclusion of a Vickers is strange here, especially at the timing it arrives and how dependent Vickers is on vet to suppress anything by mid game.
Commando ATG and mortar would give some diversity, especially if they had different abilities. Obviously costs can be set accordingly.
For commandos lul.
If you gave them a shit ton of abilities they'd become pretty OP just because the doctrine is already good enough as is. It's already kinda set to become really meta for brit players who have enough brain cells to effectively use commandos (so like very few apparently but whatever).