This card is a very nice idea, due to the fact it could be used in many strategies (including new ones based on this card) and it is unique in the way it interacts with the cards already in play.
First off, I’ll give my opinions on the subjects being discussed already. I think it should not trigger death affects. The target creature is being changed into something else – It is not dying in any form. The CC aspect is harder to balance. It would be fine if the target was something like a Crimson Dragon: The opponent would receive 3 pillars and lose a card which could have been killed by a Lightning. However, what if you targeted a Chimera? What if you used it as a form of PC and destroyed a Phase Shield? Depending on the situation, this card could be very overpowered. A possible idea is to change it so you can only target cards on your side of the field.
Anyways, on to the strengths of the card. This card is very versatile, which makes it invaluable in many decks. You can use it on your creature that is about to die, you can remove your Wings that is going to expire and get free pillars, or you can use it to create pillars for pump spells like Fire Bolt. It could also strengthen certain types of decks, for example, a mono-Earth deck could be:
6 x Stone Pillar
6 x Earth Pendulum
4 x Stone Skin
4 x Lithification
6 x Stone Dragon
6 x Shrieker
With mark of Earth. This deck would be extremely versatile and counter many strategies. Your opponent is rushing with a 30 card deck? Play your creatures, use Lithification, and then Stone Skin. Your opponent is stalling? Play your creatures, the dragons have high hp and the Shriekers can burrow. You get the idea.
Overall, I think this card is a great idea.