I don't think the ACL is optional for long term knee health. I did not have an ACL for several years following a basketball injury. Because of the biking, running etc. that I did, I had strong legs and no problems. However, I tore my menisci stretching after running one night. My personal non-medical opinion is that if you do not have an ACL, your knee can go in various positions that it otherwise could not with an ACL. Therefore, you have much greater chance of injuring your menisci which can't always be repaired. Without menisci, you have a greater chance of developing arthritis which could eventually lead to a knee replacement.
I had ACL reconstruction 3 years ago and my knee is in great shape. My only regret is that I did not have the surgery sooner. If I had, I may have not had the menisci tears.
I injuring my knee playing basketball like you. Unfortunatelly I went to see a physio who mis diagnose me and I kept playing basketball.
The end result is an ACL tear and 3 minusc tear ( 2 small latera one and 1 x 1.2 cm medial meniscus one). All left in situ by my surgeon at time of knee reconstruction. He is one of the best acl specialist in the world so I am assuming this is the best for me . I am 43 years old and my big issue is OA in the near future from all the meniscus tear.
I am wondering how you are going now as you posted this about 12 years ago and that is a good timing with regards to development of OA after knee reconstruction and meniscus tear. Did he trim your meniscus and how much ? How old are you now ?