It suggests that the piano is very worn or that the hammer butts are attached with failing brass flanges. I personally would never buy a piano with wobbly hammers. In summary, you should avoid pianos with rusty and broken strings, slipping tuning pins, or wobbly hammers. These are, in my opinion, the most common cancers in the lives of pianos. But if cost is no issue, you'll probably be better off getting a new one.
Modern pianos built by robots are usually quite uniform.
With so many moving parts, uniformity and precision is important. But even if the craftspeople from yesteryear made a fine instrument, there is the problem of age itself. Pianos are machines. Unlike people, machines never get better with age. I guess so.