Arenado will be 34 in April (Correa will be 31 at the end of September 2025) and statistically he really started to fall off last year in a few categories compared to his peak.
He played about double the games that Correa did last year (152 to 86, which is good) but in those games he was worth only 3.1 fangraphs war, while Correa was worth 4.3 in only his 86 games.
Arenado's batting line of 272/325/394 shows a pretty significant dropoff in power production too, and his wRC+ was only 2% above league average. According to steamer, he is projected to be a 3 win player.
Correa's batting line of 310/388/517 is really pretty awesome, and is 55% above league average in terms of wRC+ (or 53% better than Arenado was.) He also projects to be a 3.7 war player this year according to steamer.
And then really after that, you have the position change. Arenado is still a good defensive 3b, but not an amazing one. Correa is still a great defensive ss.
The downgrade of Correa with Lee or Lewis at 3b to Arenado and Iglesias on the left side is noticeable at worst.
The money being less would be ok if you could fill the gaps. But really, truly, the dropoff here would be a world class SS to a dumpster diving SS. And I don't want to downgrade our SS position that much.
As far as value, Correa has positive value, and would bring back a different return if traded. I'm just not certain I want to trade him at all, especially for a older vet who isn't as good at a position that is then harder to fill.
Good thing all of this is on the Pablo Lopez thread, right? :)