I personally like the more square look as it flows just like the stock rails do but is 100% better functionally as there is nothing that will snag, its the same weight and far slimmer while still retaining the use of 6 keymod slots!
From what you said I'm not sure you picked up what I'm saying. I don't think I was very clear in my explanation so I'll try again. Forget about the second picture, I'm not talking about beveling the ends as much as I'm talking about the sides.
Here is a crude rendition. The grey bars represent bevels. Rather than squared edges my preference is that side of the rail are beveled to the receiver so they blend into the receiver rather than present a block of squared off aluminum protruding from the rail.
The idea is to provide a nice smooth transition from the rail to the receiver. You could also achieve this on the ends of the rail too. You can do this with a keymod because the keymod does not depend on the sides of the rail as a picatinny rail does.
EDIT: Replying to your suggestion that there will be nothing to grab on to, I totally disagree, and if I want to add a rail panel to the KM I can do so to increase grip. A beveled side rail will give me plenty to grab on to.
Also, the corner that digs into your palm happens at the rear of the rail not the front. I don't know how you would get the rail stuck into your palm at the front of the rail. I've been shooting my SCARs for several years, so I have a pretty good idea of where the ergonomic problems exist.
If you don't see the value of machining the rail with a beveled edge, just make the rail a little wider and I will machine a bevel into it for my rifles. Part of the value of the KM design is that it allows you to make a system that does not include protruding picatinny rails with square edges. That's why KM fore-ends like the BCM KMR are so comfortable. No lumpy rails.
Try making one the way I suggested and if you don't like it I'll shut up and make my own.
Sorry, but I get a little passionate about design. Carry on. Thanks.
BTW - I ordered a couple sets of selector switches today. I'll try them out and order more if they work out. I do love the rear QD mounts I bought awhile back.