Ohhh, now you're talkin! I like it! Whats the focus of this build - casting or melee? I'm just trying to imagine what it would be doing round to round.
My Diviner took healer at level one and I like Alert as well.
Diviners can be quite funny with lucky and portent interactions.
Or just having enemies auto flunk saving throws as well.
I wondered what your angle was. Certainly makes sense for legendary resistance.
Keen mind is an amazing feat for any wizard, because it lets you:
Create accurate illusions of anything that you have seen or heard within the last month. Instant illusory copies of any text, instantly convincing auditory illusions of people etc etc.
Greatly improve your chances to teleport anywhere you've been within the last month.
Copy spells from someone's spell book after a glimpse.
Memorize your spells without your spell book.
Carry an enormous pile of reference material in your head.
Casting, your just there for the tanking: Armour proficiency (heavy/shields), defensive, second wind, con saves. You could use a weapon if you want but it would probably just make you more MAD