Russians. We would bomb everything flat into saw-dust, and then repeat if anything is still moving, a lá Second Chechen War.
But seriously, I agree. In my opinion Hezbollah has brought back the concept of irregular forces and gave it a new life in the modern world. I think that it's their ability to break up the overall war into a number of smaller engagements from tactically superior positions on their part that made it possible for them to inflict the damage that they were able to deal.
As a matter of fact the bombing everything into saw-dust became quickly part of the standart tactic of the particularly the Soviets when faced with determined defenders armed with well hidden guns and Panzerfausts in complex terrain. The "Fausters" took a immense toll on Soviet armor, even if the engineers lead the way in MOUT and infantry with submachineguns work very closely with the tanks and very heavy firepower from the ground and the air was both indirectly and directly available. But then again the defense is the stronger form in warfare.
The ATGMs of NATO caused also great concern in the WP countries. This threat caused both tactical and technological changes, but this should be discussed in other topics.
To some extent one could say that the tactical lessons of 2006 were both nothing new and truly new. Hezbollah took time-honored concepts and adopted them sometimes well and sometimes less so to specifc circumstances. That we are discussing here the performance of the Merkava shows that they got the AT-defense and public campaign partly right.
While I do think that armour will always have trouble in complex terrain there are some interesting technological developments. Combined with the right combined tactics and training integrated into a overall sensible strategy they might decrease the vulnerability of the AFV and increase the stakes for the AT-teams.