I'm more than happy to go to the galley to get a drink -- if I fancy the walk. That happens about 90% of the time. If I don't fancy the walk, I expect the FA to answer the bell. I'll ask politely ("When you have a moment could you please..."), and I expect a polite response. When I go to a restaurant and I want to order another bottle of wine, water, whatever, I don't expect to have to walk into the kitchen.
And as regards the safety vs. service issue, surely the trick is for the FAs to be seen to provide full service, whilst being completely in command of the safety aspects of the job (hopefully never to be seen)?