It sucks Legions Smart Core has been reduced to either finishing Titans that have about a bar worth of health left or taking out annoying pilots. Ronin's Core ability isn't this bad.
Hmm... dunno about that. Legion is a devastating backline player. Problem with these Titans is that they all serve purposes. There is no "i'm taking this Titan and doing everything". They all function within a set of parameters and going outside it will surely doom you.
The most versatile Titan of the bunch is Ion. Played right it's a Titan capable of being aggressive and defensive.