I would say that as long as the cylinder and crank bearings are sound, the saw should give good life after a bit of a refurb.
Crank seals can be replaced, if worn the saw can have uneven idle and can hang on to revs when the throttle is snapped shut.
The biggest issue is generally the carb, there are a number off issues that can happen and the accelerator pump is just one of them. Do the mod and it effectively turns the carb back to one from an 020T - not quite the case as the design internally is slightly different but very similar.
There are other parts I check and sort out if faulty and generally resolve the common pickup, idle and max revs issues.
If the saw is low on compression then a new piston will bring the saw back to life - the wear is normally on the piston and the cylinder is generally OK unless the thing has seized or ingested woodchip.
I have returned many of these saws back from the brink of death and if they still play up after my work, all I do is dig in harder and do the last stage of work free of charge as it is generally carb related - it happens but not too often!
A new 020T carb may be the way to go - never fitted a new carb in my time but is easier for the novice!
If the crank bearings are shot, they can be replaced as long as the crank journals are not worn!
That's my take on this - I have had some right old wrecks in my time - even bags of bits and all ended up running!
PS - Rich is right about the oil leak and the leaking crank seal symptoms. Smokey running is generally down to an overly rich mix!