I'd like to see two titans ram each other head on and the both explode, it has already been stated that titans can be destroyed by shooting at them from the outside, it just takes a lot longer. I loved ramming destroyers in the side with the battleship or aircraft carrier on 1942. I wonder what happens to the people inside a titan when it gets rammed? they would never see it coming...

As for the titan speed it has to be somewhat slow, if they go too fast people with high ping can warp through walls, this happened in the lambda class shuttle and the falcon on GC if you walked on board without actually "entering" it. but if the collision is still the same as it was on BF2 the passengers could die if they run too fast into the wall of a titan while making their way aft.