I went back and looked at the patch notes and your right, there was no scatter nerf. This puzzles me because the nebel (and to a lesser extent) used to be killing machines, now they don't seem to do much of anything.
They've always been really in-accurate, it's just the cooldown was so low it didn't matter.
Vetted up I think it was around 5-10 seconds before each barrage
This is just yet another example of Relic deviating from the mechanics from the original CoH and failing horribly.
The rockets are devastating when they hit, killing whole squads with one rocket or destroying ATG's with only a few. So what, they decide to make them really in-accurate, further adding the to "RNG" random element to the play style.
Static artillery pieces are also powerful, but again in-accurate - only being useful for attacking bases or area denial.
The main issue with static guns though (apart from their fragility) is the firing time between each shot being way too long (reminds me of the Hummel from vCoH i.e. useless at killing things).
So my changes would be -
mobile artillery: increase accuracy at medium range, increase AOE, decrease damage (especially to ATG's)
static guns: increase health, increase accuracy at medium range, decrease firing time in between each shot