#3 Davor Suker

Yes, the prolific Croatian striker Davor Suker did join Arsenal past 30, but only in the summer before he had become the Golden Boot winner at the 1998 FIFA World Cup. So it was considered quite a coup for the Gunners to sign him. But Davor Suker never really got going for the Gunners and only played 22 games for the club in which he scored eight goals.
Suker's career had well and truly dipped by then as the former Real Madrid man also struggled to make the starting-XI at his next club West Ham United.
#2 Ryo Miyaichi

Ryo Miyaichi was once compared to the Brazilian great Ronaldinho and was called Ryodinho because of his vast array of skills. However, the Japanese wide player failed to fulfill his potential at Arsenal.
Miyaichi was captured young by Wenger who spotted the former's talent early. The Japanese player then impressed in a loan spell with Feyenoord.
However, that wasn't enough for Miyaichi to break into the Arsenal first-team, and he was sent off on loan spells continuously as he made just seven appearances in his four years at the club.
Still only 27, Miyaichi, who now plays for second-division German club FC St. Pauli, has played almost 80 times for the club since joining them in 2015, but he has also had injury problems during his stint in Germany.
#1 Mesut Ozil

This is perhaps the biggest tale of implosion that has taken place with a player at Arsenal in recent history.
Mesut Ozil was once reputed as one of the best playmakers in the world and a World Cup winner who was considered as one of Arsenal's best signings in recent years.
Ozil, who has been with the club since the 2013-14 season, made 13 assists and scored seven goals while playing 40 times for the club in his first campaign.
In fact, his first few years at the club were so impressive that he even won the Arsenal Player of the Season award in 2015-16 apart from three FA Cup titles. But Ozil's time at the club quickly turned nightmarish in the 2018-19 season due to injuries and poor form.
He almost became surplus to requirements under previous Arsenal manager Unai Emery, and his work ethic and dedication were also obliquely questioned. Current gaffer Mikel Arteta thinks that it will be very difficult for the once Gunners star to actually make it back into the Arsenal first-team.
He is only 31, but it seems that Ozil's time at the top of the game may be already over.