That's an interesting argument. My intuition would've been the opposite: the title is much more likely to be dirty. 3 quick transactions in under a decade (and a fourth ongoing) means that many more opportunities for problems. Each transaction is a new opportunity involving a whole new set of people to be engaged in fraudulent conveyance or have a spouse pop out of the woodwork (as mentioned in OP).
Maybe he figured that the real safety comes from there being so many other people to sue given all the transactions...?
Patrick's point about off-record transactions feels important here. Each on-record transaction leads to an opportunity for off-record transactions to be discovered! On-record ones are likely clean in some sense, whereas 10 years of no real estate on-record transations means nobody has looked.
But to your point... the more people involved, the more moving parts involved.
Maybe he figured that the real safety comes from there being so many other people to sue given all the transactions...?