If Wenger leaves, obviously he should get a say on who his next successor should be, but let's say he decides to stay for another 5+ years and in that time Bould continues to be his 2nd hand man, then maybe we can promote Bould to the main position. The man is an Arsenal man, he has played for us, played under Wenger, coached our academy to success, learned under Wenger as a coach, so he has the Arsenal philosophy ingrained in him, and on top of that he brings that added defensive steel and discipline with him as well which makes for a good combination. I think that would be a far more ideal option than bringing in someone from outside, let the successor come from inside, and Bould would deserve it.
That's what Barca have been doing of late, promoting from within, and it seems to have worked the job and kept them stable.