I have an Armalite A2 middy 16'' barrel complete rifle. I think you can rest assured you made a good choice. Don't listen to the gear snobs that act like something is wrong with carry handle models. They have worked just fine since the Viet Nam conflict. Just because it's not the newest incarnation of the AR15/M16 platform it does'nt mean anything is wrong with it. It will serve you well. If you want to mount optics just get another complete upper with a flat top, get a flat top upper reciever only and swap it, or just mount it to the carry handle. Mounting optics to the carry handle has been done since Viet Nam also, it will work. Also remember that alot of the iron sites that are put on flat tops are basically made to imitate the ones on your A2 upper. Check out the K.I.S.S./ Isreali Defense Force pic thread. Or the A2 pic thread, you will see lots of rifles like yours that are kicking plenty of ass with carry handles.
BD