A lot of good points here, but the last paragraph made me wonder whether Pop is really so enamored with fielding one-dimensional squads playing Euro/Small-ball hybrid style, or if instead he's just been working with what what was available at the time and the price.
After a decade+ of success, Pop and RC have had to make the best of iffy late 1st and 2nd rd picks, veterans on their way out of the league, journeymen fighting their way in, and other odds and ends. Complicating matters further has always been the presence of Peter Holt's glass salary cap.
I don't think it's a coincidence that the kinds of big, physical, well-rounded, defensive players you suggest Pop is reluctant to field are also the most expensive. If Pop didn't care about hard-nosed post D, he never would have drafted Tiago or Ian, or brought Dice, Horry, and KT in, or tried out Rattliff, or signed Ryan Richards on a prayer, or even demo'd Pops Mensah Bonsu. The common denominators among the bigs who stuck with the team was their intelligence and their low price.
Likewise, guards and 3s with good size, good D, slashing ability, and an outside shot aren't often available at the bargain prices we usually demand either. Let's not even list the revolving door of prospects we've entertained to fill Bruce's vacancy, or the back-up points.
So how do you compete if you're forced to run squads that are shorter (aka cheaper) and more one-dimensional (aka cheaper)? Play to their strengths. What are the most common (cheapest) strengths? Shooting seems much more common than having enough handles to be a good slasher, so I'll go with that.
One thing Pop has seemed fetishistic and inflexible on has been finding a budget stretch-4 -- which is possibly a testament to what a pain in Pop's ass Nowitzki been throughout the Duncan era. Horry, Ferry, Turkeyglue, Tolliver, Haislip, Bonner... I may be wrong, but I don't think we've had a team without this kind of player since our 2nd chip.