Since you asked Army.
Sticking rings if not fixed will result in damage to the bores & pistons. In extream cases, piston failure.
Excess blow by can result in engine run away & major failure.
The whole fuel system is susceptible to problems dependent on the WVO. In particular varnish formation in all parts. That is fuel blockages from the tank, lift pump failure, IP damage to the elements & pressure control, Injector blockage & seizure.
The unburned varnish as it concentrates in the oil can cause crankshaft bearing seizure.
Incompletely burned liquids can cause blockage/deactivation/poisoning of the cat converter in the exhaust system (W124 & newer).
I think thats about it.

Its interesting to note that the WVO guys get a much better hearing in here than they do in the TDI forums. I have seen there they are told to go & get an old benz & stay away !!

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving