Pointed Discussion

Destroying 2 lands for 7 mana ? simply too expensive.

7 mana AND sacrifice a land, True_Smog... AND sac a land.

A pretty neato way to throw off your opponent's 8th turn! You can spend your seventh turn's mana keeping them from playing anything more than an eight drop! Devastating.

for one boom take stone rain, a possible double boom for 7cmc and sac is too much

Everyone here is really underestimating this card's potential. You don't have to cast it for {5}{R}{R}. At worst, this card is just a stone rain for {1} more, so you can always play stone rain on t3 and this on t4. However, if you're playing a dedicated land destruction deck, the kicker can come in handy. Because you can't destroy any lands prior to t3, it's hard to stop your opponent from getting a few lands out. Using this card, you can hit two lands with one card in one turn, which will help you get down your opponent's land count (and since ~50% of your deck is cheap stone rain variants, it's unlikely that you'd need your 7th land anyway).
Anyway, if you're trying to make a mono-red land destruction deck, the only cards there are that always destroy a land, with no drawback to you, and that cost <5 are:
Avalanche Riders // Demolish
Earth Rift // Flowstone Flood
Goblin Settler // Lay Waste
Melt Terrain // Molten Rain
Pain//Suffering // Pillage
Poison the Well // Roiling Terrain
Seismic Spike // Stone Rain
Sunder from Within // Tectonic Rift
I don't see how many of these cards are rated better than Dwarven Landslide.
It's no stone rain, but it's still rated far too low.

Strictly better than Craterize, which isn't saying much.