My bias is against boats that are aberations from wholesome yacht design principles, whether they were CCA rule beaters or not. In its 23 year history, the CCA rule went from producing reasonably good boats for their era, to boats that were so corrupted to beat a race rule that they ceased being good all around boats by any definition. Over the short life of the last version of the CCA rule, waterline lengths became more extremely short, and beam extremely narrow, and their light to moderate wind sail plans designed around huge genoas, the norm being 170-180% overlaps. The Morgan 45 was one of the last CCA grand prix racing designs. They went into production during the last year that the CCA rule was in use and pushed rule beating to an extreme perhaps only exceeded by Bill Luder's 'Storm'.
You can "Blah, Blah Blah" all you want, but CCA rule beater or not, are you really trying to say that a nearly 46 foot long boat with a 31 foot waterline, by any stretch of the imagination, represents a wholesome design. Are you trying to say, that a boat dependent on a 170% to 180% genoa is easy to handle. People who take boats like these cruising tend to carry heavy ground tackle
off the bow and heavy dinghies
in davits off the stern, creating a huge pitching moment of inertia, without the necessary waterline length to absorb that kinetic energy. Do you really think that is a good idea in a cruising boat?
To me a 170% to 180% genoa is an enormous sail to drag through the foretriangle, especially on a boat this big, requiring a huge amount of effort to tack compared boats designed to be sailed with smaller genoas. You can sail these boats with smaller sails, but you give away what little light air performance these boats can muster, and you begin developing high weather helm at a lower windspeed. Do you really believe that this kind of sail plan is easy to handle?
Beyond the broad generalities, in this case, I researched this particular model extensively, originally for my stepfather, and later for several other potential buyers of SJ 45's. I have spoken to close to a dozen owners of Morgan 45's and Starratt Jenks, and crawled through quite a few.
Virtuely all of the owners of the sloop rigged Starratt Jenks reported huge weather helm loads in its original form. Several said that the loads on the helm required enough strength that it precluded their wife or children from being able to steer in heavy air. The only way that they could balance the helm was to reef the mainsail early. Even with the reefed mainsail they still were sailing the very large heel angles that you seem to think is a good thing.
As to the fin keel definition, by the traditional definition of fin keel, the one that was in common useage when the Morgan 45 was designed, a fin keel was any keel that has a bottom length that is 50% or less than the length of the boat (or in some of the older definitions the horizontal length of their sail plan). That definition had nothing to do with where the rudder was located. But regardless of how you chose to define a fin keel, and whether you agree that the Morgan 45/Starratt Jenks is a fin, when you look at the Morgan 45 in profile, they have less keel area and a shorter keel root and foot than the 10" shorter waterline Cal 40. Sure sounds like a fin keel to me, and if not a fin by name, it will behave like a fin in fact.
When I think about the advantages of a full keel, I would suggest a full keel should offer; good tracking capabilities, better protection of the rudder than a fin keel, the ability to take to ground with enough keel length to reduce impact loads to the hull, and enough keel bottom to support the boat from tipping fore and aft allowing a boat to be dried out. When I think of the advantages of a fin keel boat, I think of low drag, light helm loads, and good maneverability.
In the case of the SJ you have such a short keel that you do not have good directional stability (tracking), the rudder is only inches above the bottom of the short keel, making it more vulnerable than a fin keel/skeg hung spade rudder design where the rudder is several feet shallower than the keel, and is too short to reduce impact loads or support the boat fore and aft. Similarly, compared to fin keel boats with detached rudders, the attached rudder position requires a larger rudder area and higher rudder loadings than a separated rudder with its greater longitudinal leverage. The higher rudder angles means higher drag. The reduced leverage means poorer manueverability. Whether you see this as a fin keel or not, I stand by my statement that this keel offers few of the virtues of a full or fin keel with most of the disadvantages of both.
In the end, I would give the original poster the advice that there are mush better boats out there for the dollar, especially as a first boat. Most that come to mind have a shorter length on deck, with similar or longer waterline lengths, easier to handle sail plans, and equal room down below.