Pescophile,
If you use a 7/8 MidSpey or other midbelly spey line on the Sage 8126 and a 6/7 MidSpey or other midbelly spey line on the 7141, they have very similar actions. Yes, the 8126 has a slightly quicker recovery because it is 2 feet shorter; however, they feel nearly identical to me with the lines I listed.
I have also found that many folks who prefer slow or medium rods think of the faster rods as being broomsticks. The 8126 is far from a broomstick and is really not that fast or powerful a rod. Yes, it has a very different feel than an overloaded 7141 (which loading it with a 7/8 XLT does); however, if you load the 8126 with an 9/10 midbelly line or a 8/9 XLT (which overload it), it feels almost identical to the 7141, only shorter. I have a friend with many years of steelhead fly fishing experience (57 to be exact) who prefers the Sage 8126 for summer fishing, and he loads it with the 7/8 MidSpey.
We all still need to keep in mind that diffrent people prefer different actions, some slow, some medium, some fast. Some people prefer the feel of an overlined rod, some the rated line. And neither of these variations or preferences is correct; they are only preferences of idividual casters. My preference is for fast-progressive rods like the Loop Green Series, GLX's, Gatti, and T&T, which is why I do not use Sage 2-handers, they are too slow for my taste.