So he blobbed 2 squads together, in sight and range of the mortar, and didn't expect to take losses? It must have been like that, as the motars RoF wouldn't allow that if he had been spaced out. That sounds like a skill issue of your opponent, rather than an imbalance.
He never blob, it is one single squad. At least 3 times in that game. If you want the replay, I upload it.
Don't go full retarded if you gonna say moving a Gren / PG towards a 120mm, throwing a nade, is a wrong move.