I absolutely ADORE being able to clear trees with mounted weapons to increase the length and width of my firing lines. Not only does it make those weapons seem hellaciously powerful, I can finally "dig in" into a location, develop it to my advantage and then exploit it for a win.
The urban version of it, being able to blow holes in houses, is also incredibly satisfying and tactically addicting. It looks great, every assault rifle I pickup has a grenade launcher so it can be a staple of my assault vocabulary, and I have yet to be caught on the wreckage geometry or not been able to jump through a hole I've blasted. It feels very polished.
I'm only a few hours into the campaign, but I'm completely in love with BFBC’s smashmouth firepower.