I'll second what Pete said. The BOC supports many active 4788 owners who have decades of experiance with that boat.
To answer your question here...
in terms of systems there are not any real design defects in the Bayliner 4788. I know that is saying allot, but we need to remember that the late model 4788's were the culmination of I think 20 years of production of that model line, atarting with the 45 footers.
Things like soft decks do not exist, since they are synthetic cored. I've never for example heard of a 4788 fuel tank needing replaced.
As far as systems go, you will find the same defered maintanance issues you'll find on any booat. Referigerators, pumps, head systems... As you know all that stuff needs a fairlly constant, progressive refresh.
One thing does come to mind... The crane. The 4788 has a great booat deck crane system, if a PO has maintained it, and not screwed it up. The factory stock swing arm uused a nylon bushing I think. Some owners have mistakenly lubed that bushing with petrolium products causing the bushing to swell, and make the davit difficult to rotate under load. My davit was re-built because of this using bearings so it cannot happen again.
If you get along with Blake Davis, AKA pilothouse king (not everyone gets along with Blake. I like him but he is a charachter), is a great resourse as well.
a few months ago as a livaboard and have been really happy so far. It crossed the GOM from Crystal River to Pensacola (over 300 miles) in less than perfect weather and did just great. A few mods that should IMO have been done or will need to be done are. Center engine room hatch. This is now standard on the 49 Meridian. We moved the L shaped seating on the flying bridge rearwards by about 2 feet (lining up with the wet bar), giving a great sitting area upstairs. Check that the dinghy crane swivels freely. The upper helm is on the port side and all the shore connections are on the starboard. Judging the distance doesn't take long to get the hang of. Our sliding windows didn't (silicone shut), they do now and don't leak so not sure what that was about. We cruise at 9-10 mph and get over 2 mpg. The only issue since purchase is the windlass crapped out. Makes all the right noise but gear doesn't engage. Will be checking that today. All in all a great boat for the price. We looked at several before purchase (in Florida and Alabama), suggest you do the same. No wood cores so no soft decks to worry about. Good luck!
