68-31 2.73 ERA in 4.5 years with the Cubs, plus 5-3 3.08 with 66 strikeouts in 53 innings in the playoffs. Even though YU is better, younger and has more pitches which should help him have a longer career, Arrieta is still really good.
The Phillies won 4 less games than the Mets last year, but they have an improving young team, plus added Santana and Arrieta, they also have tons of $ to spend mid season to add to team if they're close. I know the Mets had injuries last year, but they always do.
Again, nice to lump all of his numbers together, but going 22-6 with a 1.77 ERA might skew the overall numbers a bit. (And I assume we don't need a discussion about a W-L record pitching for a team that has won 300 games in the last 3 years).
As for the Phils, you're not way off, but neither Santana nor Arietta (as argued above) is a blue-chip superstar, and the Mets had a few of those on the DL for most of last year. If it happens again, maybe you're right; otherwise, I'll take the Mets over the Phils pretty comfortably.