I'm a big Fields believer but I've never once argued that he's finished developing as a passer - he's 23 years old. He'll be 24 by the start of next season. He's had good moments and he's had bad moments - such is life with a young QB. He's not a finished product but he also is doing way more than I ever expected with this roster. In context with the supporting cast (worst OL, worst WR rooms and worst defense in the league), I think he's well on his way to being a top 10 QB in the near future.
His completion percentage is up over 60%. Not great but considering the number of drops by teammates on catchable balls, it's lower than it should be. However, it's improved from a year ago and with more passing attempts (270 last season, 318 this season). His average throws are up from 6.9 to 7.1 yards per attempts, again, another improvement. Passing yards are up though not by anywhere as much as I'd like to see totals wise (2,242 this year compared to last year's 1,870). TD passes are up from 10 a year ago to 17 this season, another improvement. Interceptions are also up from 10 last year to 11 this year - not a huge change but still, would prefer it go downward. QB rating was 73.2 a year ago, it's at 85.2 this year, good improvement. His QBR was 31.4 a year ago, it is 53.9 this year (it would place him 17th at time of posting). An improvement but obviously a ways to go to be an elite QB.
Rushing wise, obviously, he's been spectacular. A year ago, he was at 5.8 yards per attempt on 72 attempts for 420 yards. This year, he's at 7.1 yards per attempt on 160 attempts for 1,143 yards. In future seasons, I hope to see him max out at around 120 rushing attempts at most (that would be 7 attempts per game). This year he was closer to 11 rushing attempts per game. Fumbles were worse this year (still an issue he needs to work on) as he had 9 fumbles this year compared to 4 last year (according to espn.com). His production touchdown wise was way better than a year ago as he had only 2 TDs last year and 8 this season. Only Jalen Hurts at 13 rushing touchdowns had more at the QB spot. Overall, 25 total TDs, 11 INTs,1 lost fumble (according to espn.com) so a 2 to 1 turnover rate, that's an improvement.
Hopefully with improved talent surrounding him, he can take the next step. It would help significantly if they could get to a league average OL and a true #1 receiver. Then we can see whether Mooney or Claypool are capable as a #2 receiver or if they're more like #3 receivers (like I believe) on a championship caliber roster. And like I've said before, if the supporting cast does improve significantly and Fields doesn't, then I have no qualms moving on from him.