One day, when destroyed models of all of the current models are built and environmental destruction is possible, heavies will simply walk through fences.

Now that would be cool, scary to see, and rather OP XD tho using forge guns to make new doors would be cool

Have a guy with a mass driver blast a hole and as the dust clears a heavy with a HMG steps through and opens up on the shocked enemies inside. Several of them go down and as the rest recover their wits they open fire and start to fall back into the next room, the concentrated fire forces the heavy to pause in his advance and wait as a logi repair his armour. Meanwhile his team mates move up and keep the pressure up on the enemy team, but they've dug in and not even grenades can dislodge them now, so you call in support. A railgun tank responds and blasts a hole into the room the enemy is sheltering in and its gunner's fill the room with blaster fire leaving no survivors.

TL;DR environmental destruction will be awesome if they ever implement it