he should stop training anything else and work on leg lock for 6 months. That way he would be able to jumpguard leg attack the same way Paul harris does.
with his level of Jiujutsu, the leglock attack game should come pretty naturally...
Yay or Nay?
Considering his level of bjj i'd like to think he has a leg lock arsenal already. 
I know he probably know leg lock attack....but he is far from a master in it.
It's not really in his personality to go for leg attacks, he doesn't seem to want injure his opponent. I am a big Maia fan, but I fear that he has peaked. He doesn't have the athleticism to compete with these up and coming fighters such as Weidman. At 34, he isn't going to get much faster or stronger, and there simply isn't enough time for him to fully develop his striking.