I've got one sticky key on my Steinway console that only sticks in dry winter weather. Jan Girardot of another forum suggesting using an "easing" tool to loosen up the felt on the pivot. This is a sort of expander. There is also squirt powdered teflon Steve's piano supply is selling for the same point. This would be expensive, as every hammer would have to be taken off.
I wouldn't start with the lead particularly. People say new pianos loosen up with playing- I've never owned a new grand so I don't know. Your injury may prevent your going through this break in process.
My new 82 Sohmer 39" console was light as a feather off the showroom floor. That and tone better than Steinway and Everett 44, were why I bought it. The Steinway was heavy, good for piano pros but I'm a dedicated amateur. I'm physically unsuited to grands generally, the heavy action wears me out, both muscles which can be built up, and joints and tendons which cannot be built up. A 50 year old Baldwin grand in the next county wears me out in half an hour. I went to the surgeon for a shoulder rotator cuff injury this spring, and the exercises he prescribed are making my elbows sore at night! There is nothing you can do if your joints and tendons are built too lightly. Most successful pianists, if you have noticed, are northern European or sometimes African background with huge beefy hands, long fingers. and huge wrists and forearms.
But anyway, I play light action consoles, some pieces lasting over an hour. Nineteen Fifties and Sixties consoles are down to about $200 now if you buy them from an owner out of tune for cash right before the carpet man comes, or $600 from a dealer working out of a flea market. Brands to look for are Baldwin Acrosonic, Sohmer, Wurlitzer, Mason & Hamlin, Chickering, Everett, Steinway 1940-?. Wurlitzer bargain line and Baldwin Hamilton had cost cutter tricks like treble string so short they don't go past the hammers, and fewer dampers than normal, so don't buy one of those - the actions have cost cutting tricks in them, too. Don't buy one made out of the USA either, the old names are used to sell bargain cost cutter pianos by the importers. Be sure to check speed of repetition of some keys with alternating fingers, the match of tone between two string and three string notes, whether the top octave go "ping" (good) or "plonk" (cheap), the tone of the bass notes, cracks in the metal plate or back,no rusted strings,no mouse eaten felt. Steinway makes some good consoles after the 1940's ones, but the newer ones are heavy and all tend to be worn out due to school use. I detest Yamahas because of the boring bass sound, and my friend's 2009 Pearl River console has a manufacturer's defect that breaks a string over and over and the Houston dealer won't repair it for free because he is ex military and moved around a lot. I've liked a seventies Kawai console, but that North Carolina factory was closed long ago. I haven't played the newer ones.
As far as filing down the hammer felt and shortning the throw, that sounds very expensive. Just regulating the hammer felt to cut force strikes me as stupid as some of the ideas the Gist Piano tech had about fixing my 1982 Sohmer. Tuners that have time to talk to you are not, IMHO, the ones that know what they are doing. Mr. Silverwood, by constast, has always said sensible things on here. he and I agree on reducing the friction being the first thing to do.