It's all relative
Sailing, as with life, is a compromise. And it's really all relative to many things, including money, ability, health, time, etc. Yea, there are boats which may be more suited to crossing an ocean than a Catalina, but then many have done it in boats which are certainly less suited. If money isn't a concern, get a Swan or a Hinckley. But since you're curious about Catalinas, I'd guess that, like most of us, money is an issue. The best way to make up for any shortcomings a Catalina may have is to improve one's ability and competence in offshore passagemaking. Large Catalina's are well built boats that should be capable cruisers. I brought a 47 up the East Coast (outside) in January. I plan to cruise the world in one soon. Not the BEST boat for the job, but adequate.