Tom, the Model 11 is one great shotgun. The downside's the advanced age and high mileage of many specimens.
The X2 is possibly the milepost for the next era of fighting shotguns. I expect developments in this area to be very interesting. Here's a few predictions....
First, the new "Serious" shotguns will be gas autos. Instead of adapting existing sporting arms, these will be purpose built fighters. Some may be built on the Kalishnikov gas sustem, like that Saiga. Others may use any number of designs that are already used in rifles and adaptable to the lower pressures and higher momentums of shotgun ballistics.
Second, modular trigger systems will be nigh universal. Why so? Because most of the parts that can and do break are in these. Field repair will consist of popping a new TG in and sending the old one back to the armorer.
Third, stocks will have some range of adjustment, maybe like the CAR-15 collapsable stock with intermediate positions. Some will also have some recoil reducing capability, like the Hogue, Precision Fit, etc. A rotatable pad will make the weapon suitable for use off either shoulder while still fitting the "Cup".
Fourth, sights will be some sort of red dot, holo,and so on.Probably the weapon will have an old fashioned bead for backup.
Fifth, an Uzi style grip safety will be used as a combat safety.Or possibly a squeeze cocker. Idea, to make the weapon safe but only an instant away from employment. A storage safety will be there for backup.
Sixth,forearms will have mounting points/rails for lights,NVDs,grenade launchers, scopes and so forth.
Seventh,a workable speed loader for faster reloads will be produced. It'll probably look something like the old Blakeslee thing for the Spencer carbine, ca 1860.
Eigthth, it'll probably be a 12 gauge. All that ammo choice off the shelf would make logistics so easy compared to R&D'ing a new, dedicated shell. However, research will produce new powders that will burn more completely in the bbl, thus reducing muzzle flash. And the velocity may be uppped a bit also, with new designs the old SAAMI limit of 13K PSI can be exceeded. How about 00 at 1800 FPS, with depleted uranium pellets?
Any ideas?....