It's more likely Robert would go from AA to MLB than A to AAA. Better talent is in AA than AAA. I would rather he gets a good bulk of time in AA. AAA rosters have a bunch of depth type of guys for when the MLB team has injuries.
I think they hope he has another 2-3 WAR season in hope of dealing him to a contender in need of a 2B (or just IF depth in general) in June/July.
But besides that, most, if not everyone, here want Rondon in the lineup.
And how many former Sox farmhands are awful or out of the game completely? Literally every team has their former prospects sprinkled around the league doing well.