I suggest you test the 2 units in game. I actually have used the Artillery officer with diversion allot and it is in much better place the A.Gren, it has smaller target and also cheaper and thus more cost efficient.
I don't agree:
Assgrens cost 40 more mp upfront, but the officer costs 2 more pop and 4 more mp to reinforce.
The officer comes at a time when it has no shock impact, unlike assgrens.
Assgrens have better RA with vet and an extra mp40, letting them outperform the officer + diversion.
The strength of the arty officer doesn't come from its combat performance, it's why the squad gets shared veterancy to keep up.
I prefer sprint over diversion, but I'd support a second vet ability for assgrens that merges sprint with lowered RA for 10 seconds (similar to UKF's battlecry).