Guehi and Tomori I definitely agree with, they should be part the first team squad now. The former never even got his chance and the latter somehow faded away after a very promising start to his Chelsea career and immediately looked a top player after moving to Milan. Losing Tomori is singlehandedly Frank Lampard's fault because he's the one who fell out with the player for a reason that's never been disclosed to the public. His loan to Milan was already signed off by the time Tuchel joined the club, and it included a buy-option for the summer of 2021 which Milan quickly activated.
In a way I understand the club and Tuchel's reasoning behind Guehi transfer away though. The club had just won the UCL title with the defenders already at the club and at the time everyone thought it would be more or less a formality to extend the contracts of Rüdiger and Christensen if the club so wished so there wasn't a clear pathway to the starting XI for a new defender last year. There was a place in the squad for a rotational CB after Zouma sale and instead of Guehi that was given to another academy graduate in Trevoh Chalobah, who ended up playing 30 matches last season. If Guehi had known he'd get to play ~30 matches over the season I doubt he'd have wanted to move to Palace so Chalobah would probably have been sold instead. Guehi was always the more talented of the two.
Livramento and Lamptey leaving is 100% down to the academy lad Reece James nailing down the RB/RWB spot to himself for the foreseeable future. The club have spent massive amounts on full-backs but only on the left side where it's been slimmer pickings as far as the homegrown youth is concerned. Here I'd say it's just a case of being unlucky that the club have produced so many good right-sided FBs or WBs in a short amount of time, there's just literally no chance to promise them all a big role.
Tammy's sale I agreed with. The price was decent and he was an awkward fit for the game system. In hindsight Lukaku was just as bad a fit, but that doesn't make the sale of Tammy Abraham any less the right move. He's a good striker and always seemed a likeable guy but there's just something missing with him to really make him a top player. That's not to say he couldn't improve in the future though, and getting to Roma where he's their first choice striker was a great career move for him.
I won't even get into the Gallagher / De Jong discussion as they're completely different kind of players. If De Jong were to join, he'd be the long term replacement for Jorginho as someone who controls the tempo of the play at the heart of midfield while Gallagher is a more of a box-to-box midfielder with a tireless engine and good for pressing. I could see Gallagher slotting into Kante's role next year but for now he'll likely have to accept either a slightly smaller role or even a loan deal away if he wants to be a sure starter.
Either way despite the players mentioned above I'd say Chelsea have done a good job in integrating youth graduates into the squad in recent years. Mount and James are the very first names on the team sheet and the likes of Hudson-Odoi, Loftus-Cheek, Chalobah and Christensen (who left) have been good squad fillers. Now it remains to be seen whether Armando Broja will stay as a rotational striker this season. I'd definitely be in favor of keeping him instead of paying obscene money for someone like Aubameyang but we'll have to see how it goes.
