I agree with Roy's breakdown. Imho, Danny's record establishes him as clearly one of the best GMs in the NBA during his tenure.
That said, each transaction should always be considered fair game for analysis and evaluation.
At this point, it is way too early to say whether the outcome of this trade is a win or loss. All we can assess at this point is whether we are comfortable with the perceived levels of benefit vs risk.
There are clearly possible futures which can make this look like an easy win (Isaiah never fully recovers, the Nets make the playoffs, Kyrie makes All-NBA, etc.) and others that can make it a terrible, one-sided loss (Isaiah returns to 100% and plays at an All-Star level for several years, Kyrie never steps up his game to a new level or worse, just doesn't fit for whatever reason, the Nets pick becomes Bagley, Zizic become Steven Adams II, etc.).
Deciding whether the trade is 'good' or 'bad' right now becomes an assessment of the probabilities of each of those future out-comes.
If you think Kyrie will likely return more total value over the next few years than the combined value that will be returned by Isaiah, the BKN18, Jae & Ante over the next few years, then you probably think it is a good trade.
If you think Kyrie will likely NOT return more total value over the next few years than the combined value that will be returned by Isaiah, the BKN18, Jae & Ante over the next few years, then you probably think it is not a good trade.
Personally, it seems to me that if Thomas does return to full health and plays out the next few years at a high level, then Irving will have to elevate his game to a super-elite level in order to validate this trade.