As Blitz you can easily proc Aftershock to continue fighting. The explosion further assist in kill potential.
This Blitz loadout focuses on snowball and Demolish lets you punish the enemy by taking towers after killing them, further pushing your lead.
Early fighting (especially level 2) heavily relies on armor to mitigate minion damage.
As a melee support you're often going to be taking poke/harass damage from ranged mage supports. Second Wind helps you sustain through some of the poke so that you're still able to take those all-ins when you land a hook.
Flashtraption on Blitz allows you to get the jump on your opponent at unsuspecting times by controlling bushing and flashing out into them
Future's Market on Blitz allows you to snowball your gold lead from successful hook kills by finishing your big purchases sooner.