I'm not terribly worried. Devs haven't been scrambling to find new software exploits, because there's largely been no need to.
There are many hackable Switches out in the wild now, and I'm sure that Devs will be able to use those to find new software exploits that will work both on this new revision and the eventual Mariko units.
Unless Nintendo releases Mariko with a completely new revision of Horizon, that patches Deja Vu and changes a shit ton of memory locations (perhaps even a full re-write of Horizon), and ONLY releases those updates to new units, I doubt there will ever be a truly un-hackable Switch.
It will just be a matter of waiting until devs release their exploits, as always.