As I said, most game cias don't actually install to sysnand, so you won't ever get bricked. Of coarse bad system titles have a higher chance. But whether or not they would brick depends on what it was you installed. Some system titles are needed for proper boot like the home menu and some system modules. (also installing a NATIVE_FIRM CIA that was bad would also brick that's on top of the usual brick issues you'd have even if it was a proper CIA of NATIVE_FIRM) You can still ***k up some system titles and have the console still boot fine. Like Face Raiders...The health and safety app or even the web browser. For those kind of things sysnand will just ignore them.
I was attempting to get the MicroSD Management app to work on CFW and I tested it with the version that doesn't use emunand. I repacked the CIA so it would install the NAND. In the end I couldn't get it to work. But installing a non signed CIA to sysnand that doesn't bork a critical boot process won't actually brick anything. On 4.x, sysnand actually attempts to boot my modified system title. But will crash out. (because it failed sig checks). But nothing else bad happens. Interestingly, I updated that same sysnand to 9.2 and now that installed system title will display the same error you'd get for modified SD card content instead of it actually attempting to boot it.
I determined MicroSD Management app is probably never going to work on CFW because it's a SDK7+ app and we know by now why those apps don't work on current CFW.
Long story short. The usual game CIAs won't brick sysnand. That is actually pretty unlikely. Just be careful of system CIAs. Those are the only ones that can get you in trouble.