Technically top loading means more space for artwork
I don't have any strong feelings about top vs side loading; NISA releases are often top-loaded (with larger boxes) and it doesn't affect their attractiveness.
With regards to the o-card, I was under the impression that it was intended to be optional and like a spiritual brother to the flimsy obi which accompany many Japanese releases. I usually fold those up and tuck them inside the boxes because I can't stand them flapping around and don't like having my collection in protective sleeves, but with TTGL I'm just leaving the box inside the o-card for now as it's sturdier and doesn't get in the way. One day, I'll throw it away and just use the artbox.
I also want to say that I actually don't want LEs to come with soundtracks
except where it's a pack-in soundtrack in Japan, too; the reason being that if it's any good I've probably already imported the standalone soundtrack by the time the physical release happens and it then feels wasteful ^^;
If it's a special CD which you can't easily obtain on its own then it makes a lot more sense as a bonus item.
R