Prosecutors are not supposed to pick the judges they prefer any more than defense counsel are. The concept is completely inimical to a fair justice system. But does it happen? You bet it does...certainly not in all places, or at all times, or in a way which could be easily be proven, for that would destroy the careers of both the person who requested and the one who agreed to such a non-random assignment.
Such despicable behavior, when it does happen, is not likely to occur with minor cases, but with major felonies; particularly violent crimes and murder. Remember, most prosecutors are elected, and the loss of a single major case can result in a lost election. The prosecutor who wants a particular judge need not be so bold as to bluntly ask for him. He can just mention, while walking through the Clerk's Office on other business, that he "sure hopes Judge X is the one randomly selected for that murder case". So everyone can say quite honestly (or dishonestly, depending on how you look at it), that no request for a particular judge was made.
In Virginia, I am aware of one jurisdiction where, somehow, all the capital murder cases end up with a judge who is not at all reluctant to impose it. Perhaps the only reason no defense attorneys have gathered the statistical evidence of that and raised hell is that they would destroy their relationships with every judge, prosecutor, and clerk in the area, thus permanently sabotaging their own ability to make a living. (It has been my sad observation that, no matter how awful a particular judge may be, even the best ones in the same circuit will circle the wagons and unite to retaliate against any attorney who dares to go after the bad judge).
In conclusion, your cynicism might be warranted, but it would probably take a careful statistical analysis of how similar cases are handled in your area to determine the truth.