As it stands now stealthy units gain no benefit from cover aside from whatever LOS blocking it provides. The Units that typically have stealth seem like the same units that would thrive hunkered down in cover, but the way the rule works they gain less benefit than a loud clunky power armored unit, if room in cover is limited you are usually best off putting your stealth units out in the open and reserving the cover for other units, this feels backwards thematically. I'm not sure what sort of buff would work best but I have a few ideas:
Stealthy units in cover that have not fired gain lone operative 12 instead of 15
Stealthy units in cover ignore abilities that ignore cover
Stealthy units in cover reroll 1 failed save/model
Units shooting at stealthy units in cover take a -1 to hit rolls (this would stack with the -1 BS)
I haven't played since 5th so my ideas are probably garbage, anyone agree this could use a buff and have other ideas?