Would THIS be the absolute ultimate home defense weapon...?

What does it weigh, fully loaded? And does it come with a carriage?

You say 41 rounds, but neglect to say that that is with the mini shells by Aguila. It will hold 25 standard 2.75" or 21 3". Weighs in at 11.5 pounds. I'll pass
http://www.thefirearmblog.com/blog/2017/01/17/new-kel-tec-rdb-survival-ksg-25/

I'm of the opinion any shotgun is the ultimate home defense weapon. There is just something about looking at that big hole on the business end of a shotgun.

No.

I'd prefer the new Mossberg Shockwave.

Wonder how those mini-shells do in gel using double 00 buck.

Short answer is no.
Best close quarters combat weapon is a 12 ga. shotgun. Just sayin'

The longer length will keep you from blowing your support hand off, so that's a plus.

Keltec prefers showing off their new guns to making them.

When they finally hit the market in a year or two, they will go for $2k.

Three years out, MSRP.

5 years out, finally under MSRP.

Keltec currently produces the KSG (occasionally), so if we are lucky, it might move move the timetable up a year or two.

I guess the biggest problem, though, is that $1400 will get you an 870P and half a garage of ammo. Or a used 870 and a defensive shotgun course.

Pass on the KelTec KSG.

Too long, too heavy, and too expensive. And possibly too many rounds (my arm would get tired shucking that many shells).

I have played with the well built DP-12 a bit.
It is built better than the KSG, but it is heavy, blocky, and more complex internally than I would want to trust long term.

This sounds like it would be similarly heavy and cumbersome.
Easy and light recoiling due to the weight, and good for putting down a lot of lead as a range toy. But for defense it is heavy enough that if you are injured you may find it hard to operate or hold at odd angles, and it is still a pump so you have to pump it.

My favorite tactical pump so far is an 870 with a bullpup unlimited stock. But I had a plastic internal break in the pump, and fabricated my own metal polymer lined replacement that holds up because I was afraid I might lose my hand if it broke again while rapid firing and pumping, as some have done with the KSG. (You can cycle these as fast as a semi auto, but if the forward grip breaks on the pump your hand can get tossed in front of the muzzle and be blown away before you realize it broke.)
Lower capacity than a KSG or DP12, but it is well balanced, light weight, shorter LOP, and has a quality 870 action in it, that is both simple and reliable.

You can bet - if at all possible that company will arrange to have one in an upcoming movie or two.... that might convince some folks...

But if you've ever have to rely on a shotgun at close quarters -when it's all on the line, a much better choice would be a standard riot shotgun (basic pump shotgun, 18-20" barrel, simple bead sight, four shot tube). That's what I carried on the street and with standard 2 3/4" 00buck it's a real fight ender. Relatively light weight, quick pointing, and very, very intimidating for anyone on the wrong end...

25 rounds of 00 buckshot weighs over 3 pounds, just for the ammo. The gun would be too heavy to swing properly.

If your HD scenario involves having to shoot 25 times without reloading, move to a better neighborhood. Or stop watching zombie movies.

From my perspective a shotgun with an enormous round capacity that can be fired rapidly is an "attack" weapon - not a defensive one. It would probably work well in fire suppression at close ranges while the rest of your crew maneuvered into position to finish the problem - but that's a long ways from a defensive role... but I can certainly see whoever the current box office hero in a firefight with one - up on the big screen.... Might even be fun to watch - but still a fantasy.

I live in the real world where there's real world consequences for every round you fire at another person. In 22 years as a cop I fired exactly one shot - and spent enough time in court afterwards to wish it hadn't happened at all....

If it comes with a cart like a civil war cannon, then I am in!

I could just see myself, buck nekkid wheeling this thing down the hallway screaming like a banshee at o'dark thirty.

Would certainly get the guy out of my house.

Might make a good range gun or something for the "zombie apocalypse" crowd, (although when I was farming, I always wished I had a huge capacity shotgun for flock-shooting blackbirds in the sunflower fields and this might be an answer) but for home defense, I think I'd pass on it. I still have a KSG on my "want someday list" and it does have the short overall length common to bullpup designs that has a certain advantage to it. However, I would still not be too trusting to a KSG until it has seen some high round counts downrange without any issues before I would trust it.
Personally, I would like to see Kel-Tec come out with a single tube design. Something more simple and less prone to stoppages due to feeding from 2 tubes yet still retaining the short bullpup length.

Not for me.

The Keltechy is too slow on the reload. Give me the Mossy Shocky.

Not for me. I like a Mossberg 12ga pump shotgun loaded with #4 Buckshot.

It's not even close to practical, but is way cool. If I ever get in a situation where I would need that much firepower, which gun I have available would probably be the least of my worries. I would love to shoot it for fun.

Umm...no. Capacity is low on the importance scale for HD, especially with ammunition as capable as 12 GA (capacity matters more with a handgun or AR). This weapon adds to undesirable characteristics such as length and weight (big-time) just for more of what won't be used. 18" shotguns are long and heavy enough already, the ideal HD shotgun would be even smaller IMO like a very reliable semi-auto 14" SBS with RDS and light.

No, but I bet it would make a wonderful battering ram.

The capacity has me intrigued. Want to wait to see if DP-12 comes out with a version of similar length with similar capacity.