If every faction loses them they have to actually use the map and they each lose the same asset, did people forget the map still exists without sandbags? Did we forget about engineers?
If every faction loses them, then not every faction loses an equal amount of power level. Ostheer with its support heavy play wouldn't be affected much. Soviet T1 would get a big boost. Especially OKW would take a huge hit because Volks without cover don't stand a chance against Rifles and IS and Sturmpioneers are already overburdened, etc. It would take a big amount of tweaking (something that can not be done in one patch) to get every faction up to scratch again.
And on top of potentially (/likely) creating major balance issues (adjusting mainline power level always has big implications), it would also require to re-evaluate all maps, especially teamgames maps, because there's significant lack of cover on certain flags that once again would make it incredibly hard for a faction like OKW to push or hold territory.
I don't mind the current situation anyway. I think only early game spam was a problem, and that has been nerfed because now you need to sacrifice map control for it. Does the nerf need to be tweaked more (further increase build time)? Perhaps, we'll see in the coming weeks/months. We can always slap a few more seconds onto it. Mid to late game it shouldn't be a problem as factions get access to a variety of tools (flamers, indirect, ATGs, tanks, etc.) to deal with them.
I do think it would've been better if Relic had not given sandbags to mainlines but foxholes (medium cover) instead, and leave sandbags to engineers, and then build the entire faction/mainline infantry balance around that, but it's too late to radically change it now.