@MarcP I don't think that call blocking has changed much since you got your phone. I have a Panasonic, last year's model, and the features are no better. I think the limit is around 30 blocked numbers.
I find with my phone, that although it can block individual numbers, my "Talking caller ID" makes it just as easy to ignore the call and not pick up, unless they call frequently. However, the telemarketers who do call frequently, will usually have a different number show up each time they call.
One feature that I would like to have (but don't) is automatic blocking of obviously fake caller ID numbers, like 000-000-0000 or even "0000" (both of which I have received calls from). The dialing patterns for NANPA numbers is pretty straightforward: NXX-NXX-XXXX. If it's a spoofed number that doesn't even fit into the NANPA format, the cordless phone (or better yet, the phone company) should be able to just block the call without manually adding every possible fake combination to the block list.