Andy put up better STATS last year. His stats are better than the past because there was no talent on the team besides Kyrie Irving. With that cleared up, I didn't notice Andy's improvement in any category.
And you're missing the point by calling this merely a first round upgrade. This is allowing us to add another potential star to the young core at 7 instead of just a role player at 24. Andre Drummond could be at 7. He has franchise changing potential. Barnes could be there. He has All Star potential. No one can be sure what Lamb, Rivers, or Ross become, but they have the tools to be more than role players.
The NBA is a star driven league. If you get the chance to sacrifice an almost 30 year old veteran big for a shot at a 19-20 year old with star potential, you HAVE to do it.
I understand you plan on contending sooner rather than later. Unfortunately your plan doesn't matter. This is going to take a little while. At most your window of contention with a productive Andy is going to be one, playoff untested year long. That's not enough for me to hold on to him over a potential young stud.