They really ought to make chaining more rewarding if they're trying to push it as the primary way of gaining EXP by nerfing the NM spawn rate so badly. I never really was a fan of the train and like that they're actually trying to encourage being active in Eureka both through that and by making the relics require monster kills, though.

On a related subject, I rather like the whole random factor of certain monsters occasionally adapting/mutating by becoming gigantic or changing into something else entirely.