Not really. I mean, it’s trivial to prevent a purge. On Siptah, you even have a placeable for that, but you can also prevent a purge in Exiled Lands.
More importantly, we have Funcom’s word about them. I once asked what the purpose of the purge was, and got an interesting answer:
That’s just the recap, by the way. The complete answer can be heard in the video and has additional details, but it boils down to what you’ve read in the recap above.
I’m not sure whether this answer is still considered valid by the devs, as the dev team has seen some significant changes since then.
However, if we assume it hasn’t changed, then the purpose of the purge aligns more with @erjoh’s idea that “the reward is the fight” than with the perception that it’s a Thrall-Dispensing Santa Event 
That said, I don’t really mind the purge being rewarding for the players. What I mind is gating that reward behind multiple layers of RNG.
If every purge was guaranteed to have T4 thralls in it, that would be better, but that’s not the case right now. (As a side note, the fact that you can get several waves without any human in them goes directly against the in-game lore for the purge. This should really be fixed at some point.)
If you could have a heavy influence on where the purge was going to strike, e.g. it picks the base that has the most relics in it, that would also be better. Or hell, just give us an equivalent of the Convergence Trap in Exiled Lands and make the purge target the base nearest to the trap.
Implement both of those changes, and you have a purge that can be as rewarding as you want it, because it doesn’t involve playing a row of slot machines before you get to the main event.