[quote][quote]I hope you can at least make a hole in a wall and climb through it.[/quote]
Wow, the spelling king himself, go spellcheck the post that a mod hasn't pulled down yet that you posted.
As for full terrain destruction: meh, it would be cool, and could make for some interesting gameplay, but it seems you would run out of map to play on fairly quickly. And really, decently built modern city buildings would take a LOT of small arms fire before there was significant destruction.
Grenades: Not actually enough explosive to do significant damage inside a decent sized room, after launching shrapnel, the unspent force will travel along the path of least resistance, at most knocking out windows.
As for RPGs, the standard today involves a dual charge, the first being a thermite boring charge designed to melt through armor, followed by detonation of the warhead shortly thereafter. In a decently walled structure, this would actually just cause a lot of shrapnel and heat inside the building, again, rough on the windows, but not overly harsh on a modern structure built to code.
So while yes, it would be cool, it would be more movie-esque than realistic, and likely cause maps to get too violently shredded to provide much functional terrain.[/quote]
Where is your basis? All the words he typed were, maybe not grammatically correct, but correct.