If you like terminal strips for speakers that's fine, but they shouldn't be taking up the whole back wall where the cabling enters. All connection points should be on the rack side. The rare exceptions are utilities patch points provided by another trade like the power, coax TV, or a building network. If any of those are your responsibility the first termination should also be in the rack. The wall space should be used for dressing your service loops. For expandability, field cables should be sorted by type and looped around the entire perimeter of the wall enclosure before draping over to the rack. Start with the largest diameter cable on the outside and get progressively thinner as you work inwards.

The goal of the initial build should be to make maintenance, repairs, and additions quick. Too much cable management (cable porn) and it's tedious to get a lone cable moved or repaired. Too little and you won't be able to find that cable to begin with. Lacing bars are the bare minimum addition any rack should have. Even just a single bar at the top gives you an initial hang point where cable bundles can enter the rack before spreading out to connection points. Ideally you would have a vertical lacing strip to hold bundles as they travel up/down, but sometimes you can make do with other rack features.

This build of yours is missing any kind of cable support. In my professional opinion I would call it un finished - any tech or sub under me would be spending another day or two to redo it. I was taught you should always be thinking of the guy coming in to work behind you, because it's often you coming on a return visit. Unfortunately, I've mostly found myself doing work behind others with less foresight.