Just read all 9 pages. And I am still confused about exactly what you are looking for.
But I think you are getting on the right track with sizing.
Your mistake is trying to compare a Deere 3000 series or a Kubota lx with a Ford 3000.
A Ford 3000 would compare to a mx, large grand L or Deere 4000 series.
Quit using the terminology like utility, compact utility, and mid size utility. There are no hard and fast rules that define those sizes.
Rather look at 3 things to get a "feel" for tractor size. 1. Weight 2. Tire size 3. Wheelbase. And rest assured there are dozens of models today that compare real nicely to a 3000....with similar HP.
Another thing to consider is that HST tractors are less pto HP than their gear siblings. So while you are glazing over looking at specs...this may be some of your confusion about today's tractors being under powered.
But in general....tractors of today are a higher HP/weight than tractors of the past. The 3000 ford was known as a high HP to weight machine. But even it can be best today with several models that have a higher HP to weight ratio.