In terms of a PvP 1v1, in comparison to the Python, the reduced defence (on any comparable min/maxed build, Krait would have lower base shield, fewer SCB's and/or less hull hp) seems a reasonable trade-off for the Krait having higher speed and (probably) overall manoeuvrability.
The real question mark for me is over when or if Frontier will introduce some form of SLF pilot immortality (or, at least, reduced mortality). An Expert SLF is a considerable advantage in a long duel. A Deadly SLF is a massive advantage. If everyone ultimately grinds up to immortal Elite SLF's then assuming comparable PvP piloting, the Python guy wouldn't stand a chance.
EDIT:
We can see on the vid that Krait has 490 Mj with 6A shield and 2 x A boosters. Python would have 557 Mj. So Krait will have smaller shield unless something changed before live.