They really don't have lots of flaws compared to other similar boats or similar price. And I say that as someone who owns one, but is not blinded by flaws. If I had more money, I think I would like to own something else. (How about a Peterson 44 or Brewer 44?)
They are well tempered boats and quite comfortable in a seaway, in general, with great accommodations (especially if you get the over-under single bunks in the forecastle) But . . .
For a cruising boat, they are a squirrely broad reaching and downwind, to my thinking. Others, not used to full keel boats, might not agree. The Landfall will be no better in that department and maybe even worse because of the more extreme ends. The autopilot I have (CPT) will sail the boat on a broad reach, but it works hard and the boat yaws quite a bit. Several boats use Monitor vanes successfully. (By the way, I was wrong about Landfall depth in my initial post. I was thinking of the typical racing 38. Landfall is 4'11"--same as most morgans.)
For long distance cruising, their limit of positive stability is close to the minimum of 120 degrees (about 125, according to US Sailing.) If I were in big seas, I would feel better in an old Rhodes or Alberg or S&S design with 140 degrees.
Morgan's hull and deck joint is screwed and bonded with some sort of sealant, not bolted. I think that is a flaw, but no one has ever complained about failures there. You could fix this with lots of work.
40 gallons of diesel is not enough for long distance cruising, as far as I am concerned, but there are several Morgans that have gone ocean cruising.
The rig is a 1970s design--big foretriangle, smallish main. that is accentuated on the 383/4. You can make the boat a cutter, but that takes some doing. A much more foregiving design for cruising would have more mainsail and less jib or genoa. For the inland cruising that I do, however, the rolling genoa is nice. I also carry a retractable solent stay for my working jib and storm jib.
The boat was laid up before vacuum bagging, kevlar, and vinylester resin. Pound for pound it is not as strong as newer boats--but frankly, I would much rather have a solid hull below the water line (the Morgan) than something that is balsa cored top to bottom (C&C, I think did that.)
The bulkheads are not tabbed to the cabin top and deck. There is debate about that, but I think such tabbing is far superior for ocean work or heavy weather work of any sort.
The anchor locker is either too small or not quite well designed for carrying lots of cruising anchor tackle--but it is almost big enough and you can carry extra rode below, down low where it belongs.
Some early Morgans had a construction flaw. Eliminated part way through the 382 run, recalled and repaired later, and no similar problems with the 383/4. It is not clear to me that the initial flaws were all completely repaired by the recall effort.
The mast, at least on my 382, is a telephone pole without any taper. That puts unnecessary weight aloft, but was cheap.
Deck fittings, including stantions, mostly do not have full backing plates, but you can, with some substantial work, fix that.
Cabin handrails are not through bolted, just screwed on. That can be fixed, again with work.
The forward cleats are probably inadequate for anchoring or sea anchoring in extreme conditions. I have not figured out what to do about that--and avoid extreme conditions. I don't think any tupperware boats without old fashioned through-deck bitts has adequate ground tackle attachment points.
In the first or second set of archives, you will find a discussion of "fatal flaws." What you will see is that one guy in San Francisco got a deeply flawed boat early in the production run and that the boats are not without some flaws. Don't buy that guy's boat.
If you hit a reef hard enough, you are going to hole your boat--but that is true no matter what tupperware boat you get. In a perfect world, all long distance cruisers would have radius bilge steel yachts.