From interview with Tim Willits: we need to pickup sand clock for faster regeneration.

From my professional opinion: We need about 50-100-200 tasks in game. Each task gives some regeneration(duel only).

-Air rocket
-Combo(PG+RL , RL+RG etc)
-Hattrick(3-4 frags in a raw)
-Impressive(4 rails)
-2 frags in a row with Machinegun(or ShotGun or 1 from Grenade)

-We know DEFRAG, so you make some difficult(short) tricks on map(by time or just reach some point on map) and it gives you regeneration

-You control perfectly only 2 yellows on ztn for 2 minutes without your death.

-You not take damage from enemy for 2 minutes.

- You fully blind for 20 secs

-You fully deaf for 2 mins

Each task gives you special amount of regeneration.

No need for sand-clock.