I have a suggestion for an enhancement for "check host .. with address .." when adress is a domain name: Currently (monit-5.13) checks all addresses found, and it's OK if one succeeds. Today many name servers do address rotation, and if one of the addresses returned fails (maybe because it's not correct) the check succeeds.
I suggest an addition to specify whether to check just one (the first) address, or all addresses returned by the resolver.
What about changed "with address .." to "with first address .." ot "with all addresses .."?
In the latter case, you could even allow a list of literal IP addresses if you think it makes sense.