I guess you can knock the sound they make, but mortars in CMBB are far from lame. Take a German 41 rifle platoon's three 50mm mortars, attach them to the Company HQ, and you have a nice support element capable of knocking out field guns and AT guns or suppressing entrenched infantry. I use 'em all the time in assaults and they've proven themselves invaluable. Take a pair of onboard 80mms and you have all the perks mentioned above, plus you can lay down smoke in a very pinpoint manner in front of enemy positions.
On the defense, use a couple of light mortars and MGs against enemy infantry caught in the open, and you pin them in place for the heavy tubes represented by your FO.
I just love me them CMBB mortars
If you want to tweak the sounds -- there must be a mod pack or two out there, just like there was for CMBO.