Not so sure that we even need to indulge our personal appetites for impracticality on this one. Although it is the bread and butter of sports forums, impact is a funny thing to extrapolate/interpolate from data that for the most part doesn't exist...
We all know that life is an imponderably large series of decision points. Do we go left or do we go right... the consequences of our choices are made crystal clear to us, but there is nothing to suggest that we would meet the same consequences had we taken different actions. The only thing we can know for sure is that but we can never know what would have happened if we had taken the path we didn't choose.
So given that ridiculously obvious introduction, I believe that we can't assume that Catchings injuries, would still have happened if she had come to us... who knows... another possibility would have her career badly decayed... we can't know these things, so it makes little sense to look at the consequences of a player's decisions for guidance. What does make sense is to look at the native talent and basic character attributes of a person if we would like to make merely harmlessly horrible guesses about what different decisions would have brought to a players career and to the team for which she might have played..
And then there is chemistry. Catchings was a pure Geno player. TC would be a great fit no matter where she would have gone because that was one of her special super powers -- universal chemistry. As much as I admire Griner and am happy to see that she has grown and found better footing in life, the inner turmoil that was so much a part of her college years would certainly have been an issue wherever she chose to go because that turmoil was so central to her life at the time. And let's remember, Geno doesn't do player angst. He's a wonderful guy, a spectacularly gifted BBall mind, a great coach, but dealing with deeply seated player turmoil is not one of his super powers. If she had come to UConn she may have spent an incredible amount of time with the swim team. Who knows... Griner might have won Olympic gold in Freestyle and Butterfly had she come to UConn!!!!
When SS played, UConn was just beginning to gel under Geno's leadership and I really don't see her bringing us a championship in 1992 or 1993. Had she played for us a bit later (make that after she graduated) I think that she might have made the difference. 1994 is a case where she may have helped. 1996,7,8,9 are possibilities too, but they are all years that would require the NCAA to give us a waiver to allow a college grad to play for a college team...(tongue meet cheek)
Overall Swoopes would be a good choice too if we are talking players and not championships, but I'd still choose the special talents and chemistry of Catch any day even wrt impact(especially since she played during our lean years of 1997,8 and 1999.
Boo