If I remember the general sentiment, it was that on offense, Tampa was well set at the skill positions but a big question mark with the offensive line. The thought was they were very much the opposite of the Patriots in being built "outside in" with star receivers/TEs but lacking the protection. Also that they were lacking the fundamental approach the Patriots take (short, precise passing) in favor of "throw it up there and make a play" stuff.
A lot of that thinking was just plain incorrect, especially coming from a Patriots fan perspective who tend to see things in black-and-white. Yes, it's true that their offensive line wasn't great, but we should all know that the quarterback has so much responsibility in this. I think most people realized Tampa's offense was pretty loaded, though, with Evans, Godwin, and Howard, along with plenty of resources to add more guys; once you have the star players, adding layers of contributors is a lot easier.
On defense, a lot of people in this very thread picked up on their very good DVOA in 2019 contrasted with the points allowed, noting what 33 interceptions will do to a defense. On paper, they had a good defensive team even before adding Winfield, and while their secondary doesn't have big name star players, they are pretty solid overall. But also, it's not like their defense was actually playing at the level of the 2000 Ravens all year; they got really hot at the end, were healthy, and were very fortunate to face (a) Brees, who had no arm left, (b) Rodgers, who lost a $23M left tackle weeks prior, and (c) Mahomes, who was down both tackles. All of these teams ran into the teeth of that defense, a swarming front 7 who also have the ability to cover tight ends and RBs in the passing game (a strength of the Saints and Chiefs, again).
So overall, I'm not that surprised that they put it all together, but I also think that team is probably 8-8 with many QBs and even with a "good" QB like Rivers are probably a one-and-done playoff team.