I am happy with the trade-off. Particularly because of two things:

1) I know they will push updates for security patches right away (as I've seen them do in the last year).

2) I know they'll create backups and snapshots as they do updates, which you mentioned above.

These two things are parts of what I love. And I don't mind that core updates show up in a week. If I want, I can always make it happen faster by doing it manually.

So in the end, they support the concept, but implement it differently, which is fine by me.

If they were to allow people to change the config, I can only imagine what would happen later when someone (who didn't know what they were doing) complained that backups weren't taken, and WP Engine would have to explain that they let the customer hose themselves.

In the end, the value proposition of hosting with them is that I can step out of the role of sys admin and they can "manage" it for me - so that I can't hose myself. Like I said, I'm happy with that tradeoff.