Eight years GS here. I've seen no overall change (other than the "policy" issues such as clearing RPUs/GPUs within 72 hours if > 3 seats available, etc.). GS has been there when I need them. At my home airport, BOS, things have in fact improved over the years. There's a dedicated team, many of whom are the most senior at the station. They know all their regular customers by name. We are boarded before pax with disabilities by a GS agent who is at every departure. If things go south before we arrive at the airport, we are proactively called with advice/alternatives.
Sure, there's the occasional telephone agent who either doesn't understand the policies or procedures. I just HUCA and the next agent nearly always gets the issue taken care of.
Combine this with the stated benefits published in the Wiki, I'm a happy GS flyer.