Seen by who? Relic noob players? Because i have never seen community complaining about cover being too powerful.
Buildings cover are ok as they are IMO. its more realistic. to get the unit out of it you need flamers, mortars, heavy vehicles...I like how we see mortars more often now.
But I agree on most of what you wrote.
Buildings are not balanced. It takes 2-3 grenades (60+ munition to clear out 1 building) and flamers can take 5-10 seconds of burning to remove a squad. This is excessively to much.
Mortars and vehicles do not do it right either. Your more likely to absolutely destroy the full health buildings before you kill the full health unit inside.