We only block pakistan, as they have most ridiculous amount of script kiddies!
But i believe blocking lot of countries is not a solution unless contries like pakistan, and yes usa has alot of 'bad' traffic so the only 'safe' (with very few compromises, manageable) measures are having a robust security suite like cpguard/cpfence/monarx (haven't used, but has good rep)/ and immunify 360 (top of the line, but unfortunately still not available for enhance), everyone i guess offers decent bot protection and IPDB protection, WAF, etc.
And then use cloudflare on top of it or encourage clients to use cloudflare..
Blocking countries will help yes but has lot of downsides like you are limiting your client's potential traffic which might be their potential leads if businesses.. unless you are absolutely sure your customers has nothing to do with blocked countries. At the end we still may face incidents, you never know!!
