an issue with the lint and how it was collected
Yes there is an issue, for some reason the 27" would catch more lint if the felt on the filter was a 1/8"-1/4" longer to seal better around the grommet of the front bulk head exhaust system. Does the lint comes out completely when removing?
No, some will fall out and blown through the exhaust system so in these days and times, the shorter the vent, the less chances of lint buildup through out the whole system.
The 29" directs the exhaust air towards the bottom center of the filter and works it way up and the edges of the filter containing the lint better when removing from the dryer, think of it as a train on a track, when pulling the filter, the lint stays on the filter and slightly compresses against the bottom edge which helps prevent lint fragments falling back into the rear bulkhead.
The 29" A well design machine is very easy to take apart and fix if needed!
Usually the High Heat Thermostat (Electric Dryer) or gas valve solenoids (Gas Dryer) will fail before the belt goes....
Timer failure does happen but are far a few.....