Sure, you'll get a few phone calls - that's what call display is for. And with the new Do Not Call list, such calls net the caller an $11,000 fine. Haven't gotten one since I put my number on the list, so even if they harvest the phone number, they can't use it.
So wait, guys trying to get illegitimate access to my machines and/or steal my identity and calling through "unavailable" VoIP lines from Russia and Nigeria are going to respect the US's Do Not Call list? Get real.
Also, even though my contact information is unavailable TO YOU, it is not unavailable. If there is an issue, my registrar does have my full and complete information (and they are required by ICANN to confirm it is correct periodically, which they do). Perhaps not all registrars follow the ICANN rules, but that's ICANN's problem, not mine. Getting rid of private domains won't solve that problem at all. If a registrar is sloppy enough to not keep the full information on file, I'm pretty sure they are sloppy enough to put fake information in WHOIS too, so what's the point? It solves nothing and harms only the legitimate domain owners.
For the record, I didn't complain. I solved the problem by removing my WHOIS information from a public database. There's no reason for it to be out there. If there's a legitimate issue with my domain, my registrar is required by ICANN to contact me on their behalf. If there is not a legitimate issue with my domain, people don't need to know my information at all.