I really like Havertz and think he'll be great in this Arsenal team.
Transfer after transfer Chelsea keeps making even less sense, their midfield and striker options are horrible.
People might think 'OK, they will buy a few players' - sure, they might. But they cannot bring quality players without CL football so I don't expect them to fill these spots (Havertz, Kovačić) with better players.
Yeah, Kai Harvertz for Arsenal would be great, when I watch him play, who I really see is Mesut Ozil, They lacked strength but they're really both technically smart and tactically ready especially during big games. I don't really know Mikel Arteta's plans for the new season, but I'm sure they'll make a gream combo from Declan, Kai and Odengaard.
Chelsea has lots of players to replace, Brighton Caicedo would be a good replacement for Ngolo Kante. With Mason Mount wanting to move, still not certain though they ain't have agreement ( Chelsea and Manchester United ) Plus replacement for Kovacic and Kai is something that can't be replaced this season, they'll struggle if you ask me. They've not made good signatures after all the push outs of these players. The start of the season would be a bumby one, if they don't get quality midfielder's to support Enzo Fernandez.
Chelsea sold a lot of players and that proves that this team is making a very big overhaul for next season but I don't know and am a bit pessimistic that it will be much better because of the many talented and good quality players they are selling at the moment.
Harvertz is a young player with great potential, I am also a little surprised that Chelsea will let him go following Ngolo Kante who will also leave for the Arab league so it is certain that Chelsea's game will change drastically for next season, the big changes made by this team are few risky in my opinion.
And regarding Harvertz who will join Arsenal, of course this will be very good for the player to improve his career because the Arsenal team is currently very good and growing, thus allowing the player to have a much better career with a good team.