You've got the jist of this as quite simply, Klopp and this Liverpool team are way ahead tactically. In fact, to be precise they are 12 years ahead.
In a vacuum, if you transported the 08 team to today and played them against even a few of the Premier League teams, they would probably 'struggle' because the coaching and tactical shape of teams are much more fluid. The whole is greater than the sum of its parts etc.
However, if you gave Fergie, say a year to adjust and play in the league, that 08 team would destroy this Liverpool team just like they did to Arsenal back in the days. They wouldn't try to play possession, they would just defend solidly, pick the moments to play and break the weak links. Technically and physically the 08 team are in no way inferior.
Just imagine your midfield or attack losing the ball in transition and you have Ronaldo, Rooney, Tevez, Evra breaking in waves with Carrick/Scholes feeding the ball. Or imagine VVD (because none of the others are dominant aerially) having to deal with Vidic, Rio, Rooney, Ronaldo and Brown on set pieces.
This Liverpool team is rated because of their incredible efficiency and productivity based on Klopp's brilliant coaching but on talent they are comfortably behind the 08 team.