I think it's worth it to at least clean the innards and regrease it. There's at least one youtube video on how to overhaul this model. It appears to be nicely designed and not too complicated to work on.
There are much better greases available than the ones that Hobart ships in these mixers (and that they sell under their own brand). I'd seek advice from a lube specialist on the ideal replacements for the stock grease. Some of these mixers use one or two different viscosities (and the bigger ones use oil in the gearcase).
You're looking for, generally, a synthetic grease with FDA h-1 food machinery rating. The synthetic greases last much, much longer than the conventional mineral greases. They also prevent wear better, and work better at high and low temperatures, and are less likely to separate and drip into your food.