Nobody can tell someone else what they "should do" with an old upright piano if they love it. I will say there is a certain sense of diminishing return with old uprights beyond just general tuning and upkeep. Monetarily speaking most are not worth spending a bunch of money on to hot rod them. And some of that is piano specific and also location oriented. The thing is around here old uprights are unsalable basically, I doubt anyone would do what you are considering having done when they are trying to figure out how they can get the thing out of their house for free. No offense intended, just the cold hard facts.
I appreciate your opinion 'to ditch the thing, but keeping it is the right think for me.. the quality of tone, construction, and action far exceed what I could purchase, and in a 52 inch upright. My total investment will be a fraction of a new Yamaha, and with the darker tone I prefer... not to mention an African mahogany cabinet. I am asking for advise on the weight of the keys with the regulation, not whether I should ditch the piano.