Where are people drawing the conclusion that the teams 5-20 in the other top leagues would piss the equivalent in the premier league? The quality of players in the midtable sides are staggering right now, you have players like Shaquiri playing for stoke, and Cabaye at Palace.
The teams you would associate as the "top" clubs in the prem, supposed to be challenging in europe are United, city, arsenal and chelsea compared to those in the other big leagues have declined in quality compared to the likes of Barca, Madrid and atletico in spain, and Bayern in germany. Probably even PSG in france right now.
Other than the very top of world football, I would back the english clubs against their european counterparts 90% of the time. outside of the top 4 you have Very good sides like Spurs, liverpool and everton who would beat the likes of villareal and sevilla. or Shalke, leverkusen, gladback etc. Napoli, the milan clubs and roma.(sorry for the spellings)
The quality has been spread amoung the league and the top clubs need to get their act in order to compete in europe, but the league is strong.