They've made some questionable signings and trades in the past. Preller has done well with some like acquiring Musgrove, signing Machado, trading for Profar, and signing Darvish. Though he has made some awful moves like with Justin Upton, Matt Kemp, Eric Hosmer, Will Myers, Ha-Seong Kim, and some of the trades like for Snell, Manaea, Clevinger haven't really lived up to the hype because of injuries.
I'm shocked that they have been able to stay relevant after some the baseball decisions they made. They've done a fantastic job at drafting and developing prospects, which you have to give them props for. Otherwise, a lot of baseball decisions in terms of free agent signings and trades have been 50/50 and would lean more towards questionable.
They need Tatis at 100%.