Sancho has a history with City/Guardiola and apparently did not leave on the best terms. It is no wonder that City would prefer to sign someone who doesn't have this history Sancho has there.
And also it is obviously true that Sancho and Grealish have a bit different playing style and one might fit better for a certain wanted profile than the other.
But if you say that Grealish is more proven than Sancho I just have to agree with Hansi - while both have a similar amount of games in the top national leagues (Sancho with much better stats in a bit weaker league), only Sancho is proven at the highest stage of club football, while Grealish never appeared in the CL.
I did see very little of Grealish so far and therefore have to trust your observation regarding the quality of his scoring. But when he is so much better than Sancho, why does he score so rarely? Sounds to me a bit like he is massively lacking the consistency in his output that Sancho has proven now for years.
That's true on the point regarding Pep and City, you're right.
On Grealish, he is not "so much better than Sancho", but he is better currently. Not to say Sancho won't get better as he is still very young. I think really the best way to judge him is to watch him, or watch his highlights vs an individual team to see how he does in one game. His passing range, dribbling, and to a lesser extent his finishing are all top drawer.
I think the lack of numbers comes down to really the quality of the team, 19/20 was their first season back in the premier league and their main striker signing got a big injury, the 2 backups (Davies and Samatta) managed one league goal between them. Their other wide forward player was usually El Ghazi or Trezequet, and neither score or create many. 20/21 was better, they signed Watkins and Bertand Troare, and they were averaging about 5th spot before Grealish got injured. I think next season they'll do even better as they're trying to make good attacking signings (with Buendia signed currently who I rate very highly).
Sancho has shown very good form in the CL as well as being absolutely world class in the Bundesliga for 3 years. Is the premier league the be all and end all now? No other top league counts? I'm not sure how Grealish can be more proven. He's more proven in the premier league. Not in top leagues of European football or continental football. Not in terms of minutes played at the highest level. Not in terms of actual stats on paper with their goals and assists.
Grealish is brilliant of course, but Sancho is far more of a goalscorer which Grealish provides almost nothing with, while both are pretty similar in terms of creativity overall between their dribbling and passing. It's fine if you want to say that's purely because Sancho is in a top team in the Bundesliga compared to Grealish being in a mid table side in the prem, but Sancho's performances as an 18 and 19 year old in the Bundesliga destroyed what Jack Grealish did in the championship before they got promoted. And same with Grealish's first season in the prem. It wasn't until this season (where he was injured for a third of it) where Grealish put up elite creativity stats on par with what Sancho has done for 3 years.
Here's a comparison of them statistically (how they rank per 90 stats as a percentile with other attacking mids and wingers in the top 5 leagues in Europe). Sancho isn't a world class goalscorer, but he provides a solid amount and has averaged about 15 goals a year. Between their passing and dribbling creativity and the influence in the build up, they are right up there with each other as some of the most elite in Europe. Like I said, fine if you want to equate it to being Bundesliga buff vs Grealish in the prem, but that's just purely your opinion driving that rather than anything being "more proven", as with Grealish we are talking a much shorter amount of time displaying this form despite being 5 years older, and with Sancho we also see him excel in the Champions League.
There's a serious problem with focusing only on stats, you lose a lot of the background information. Mathew Benham, the owner of Brentford who recently got promoted and had a rep for being stats focused to sign players, talks about this well. He mentions how while they do use a lot of stats, to charecterise them as a stats only team is wrong, because stats inherently have a lot of noise and you need to watch players and teams a lot too to get the correct information. Stats leave out all the information regarding the shape of the team, the amount of chances they create, how many goal scorers they have, the quality of the goal the players score etc
For while the points of stats you've shown are true for Sancho, there's several things you don't take into account
- You say Grealish provides almost nothing in goal scoring and that Sancho is far more of a goal scorer, but he scored 8 goals for them in 19/20 in the premier league, out of a total of 41 goals the whole team scored in 38 matches. That's 19% of all the goals. Sancho scored 17 goals out of 84 goals total scored, and that's in 34 games vs 38 games. 20% of all the goals, a very similar total. In 20/21, Sancho scored 8/75 goals in the league, for a total of 10% of the team goals. Grealish scored 6 out of 55 league goals for Villa, coming to a very similar 10% total. So the point about one being the better goal scorer is not really true just because one has scored more goals, when you look at the team statistics and the type of goals scored.
- Using not being in the CL against Grealish is wrong, when he's never had a chance to play there. Also the point of Sancho 'excelling' as you say in the CL is clearly not true, just because he's played it in doesn't mean he's been good. In 18/19 they went out to Spurs in the Round of 16, on 4-0 on aggregate. I watched both matches specifically to watch Sancho, and he did nothing in either match. In 19/20, they went out to PSG again the round of 16, again I watched Sancho closely. He was a little better than in the Spurs match but it still wasn't a great two matches from him. He didn't play in the knockouts this year and if anything Dortmund were unlucky to go out to City in the QF's this year without him.
- You say Grealish stats in his first season were not great, but his assist numbers would be a lot higher if they had a fit striker. Their main striker, Wesley, got a serious injury early on in the campaign. Their two backups, Samatta and Davies, got 32 appearances between them in the league and managed one goal. The main change this season vs last was the signing of Watkins. Next season it'll likely go up even more as they've signed Buendia who is both a good goal scorer and an assist maker.
That said, I don't disagree with some of your points, Sancho has shown more at a younger age. What he does have over Grealish, is age and the time to develop. Just right now, for me, one is clearly the better and more polished player, and carries less risk as a signing (albeit a higher price tag). But I get what you and others will argue, especially considering age and stats, but it's just a personal opinion for me having watched both an extensive amount over the last 3 seasons.