What? You're saying Depay want to leave because Lewandowski will replace his position and at the same time, you're supporting Depay to join Arsenal while Arsenal already have Gabriel Jesus that will always on starting line up. Lewandowski can injured too and if Depay is a good player, he will substitute Lewandowski. The reason why Depay want to leave Barcelona is he don't want to become a substitute player.
Subs are not always bad, in Depay's eyes he wants to be in the main squad, but his role will be very useful. He was key in anticipation, but I also can't blame him when he wanted to be a mainstay at Barcelona, without that request he couldn't hold back any longer and kept raving about wanting to leave. What is certain is that Xavi as Barcelona coach knows what his team needs at this time.
Depay must end his time with Barcelona, he will find it difficult to break into the main squad after Lewandowski arrives. Moving is the only way to save his career, Tottenham are very interested in signing Depay, he can move to Spurs for guaranteed playing minutes. Depay's departure will also leave the number 9, so Lewandowski can inherit the number 9 left by Depay.