I'm not sure it's that true that EPL grounds are that much smaller than European grounds, at least for the "Big Six" (and Wembley):
City of Manchester Stadium
For non international matches, the pitch size can vary quiet a bit. The pitch has to be a rectangle whose width can be anywhere from 45 to 90 meters, while the length can be anywhere from 90 to 120 meters. So a football pitch can almost be a square!
However, the international pitch dimensions are much stricter. The width has to be from 64 to 75 meters and ...
The pitch most definitely varies in size, but not terribly much. See this page from the BBC for example. England's rules are very wide - the pitch must be between 90m and 120m long, and between 50m and 100m wide (!!) - that's a big variety, though - but for major (or even mid-level) play, it's pretty close to standardized.
This page lists various Premiere ...