The main reason Ruger created the RAP was to throw their hat in the ring for the new military standard sidearm contract. They pretty much catered to the specs of that contest, which included things like having a modular frame with interchangeable grips and grip frames, available in common NATO calibers (notice they came out with 9mm and .45 ACP first, no .40 S&W?), and an available manual safety (the RAP is available with and without a thumb safety). If the compact- and/or subcompact-sized versions of the RAP fix the stupid squared shape of the rear of the grip frame, that would help things out a lot ... although I still don't see myself getting one, simply because it doesn't do anything that the Glocks, M&P's, XD's, or particularly the Sig P250 and P320 don't already do just as well (if not better). Sig similarly dropped the ball on making their .45 ACP only a 10-rounder, and I dunno if they're going to add a thumb safety version to submit the P250/P320 for a bid, but at least their grip frame actually feels comfortable to hold/shoot.
For that matter, I dunno why no one in the military's really considered the Rock Island Armory double-stack 1911's in .45 ACP or 9mm, especially since they're just basically wide-gripped 1911's (14+1 capacity in .45 and 17+1 in 9mm), and there are some units still using the classic 1911 design to this very day, so it's not like it's an all-new design or anything. Heck, my .22 TCM/9mm RIA 1911A2 even fits all of the standard 1911 Government-sized holsters that I have, so there's another cost-saving detail right there - just use the old WWII- through Vietnam-era holsters!
To me, the RAP is more a copy of the P320 than it is a ripoff of anything Kel-Tec has done. Of particular note, when you slide the frame out of the grip, the RAP's trigger assembly doesn't jump apart and send springs shooting across the room like my P32 or P11 did the last time I took them apart.
