Given some of the contracts we've seen handed out to free agents in recent years and the fact that Trout is only 22 and is arguably the best all-around player in baseball, this might seem a relatively modest deal to some. But we have to consider the structure of MLB salaries regarding service time.
Trout isn't even eligible for arbitration until next season and he can't hit free agency until after the 2017 season. Thus, he won't even make $1 million this coming season -- sans an extension. The highest ever first-year arbitration salary was Ryan Howard's $10 million in 2008, too, so Trout getting around $25 million per season for this year and next would be a massive uptick over what he's expected to make without an extension.
Not only that, but a six-year deal would mean Trout would still be set for free agency at age 28. Basically, if this is what's being discussed, it's hard to find any negatives from Trout's perspective.
Trout hit .323/.432/.557 (179 OPS+) with 39 doubles, nine triples, 27 homers, 97 RBI, 109 runs and 33 stolen bases last season. He finished second in AL MVP voting for the second consecutive season to Miguel Cabrera.