Build recommendation for WRT3200ACM?

it's not worth the trouble
you could not save changes on sysupgrade, but you should not get any troubles if you save them.
if you save the changes, delete the /etc/config/wireless and recreate it using wifi config
if you want to revert to kernel 4.9 ubifs partition will need to be force erased [solved] Wrt3200acm 4.14 downgrade to 4.9 ubifs problem