The fact a couple of guys did better from a statistical standpoint means virtually nothing. The BA's against are less of a story than ERA. I'd just guess walk and/or power rates are up more substantially to create that 15%difference in ERA. Where available, runs are the preferred measure.
Beyond that, I've learned not to judge hitters by the conversion factors of pitchers or vice versa. For instance, if the parks are small, pitchers can gain a benefit by moving to larger major league parks. That means hitters get a double dose of bad news, though (i.e. leaving both a weaker league and smaller ballparks to go to a tougher league with bigger ballparks). The example may or may not apply to Cuba, but it illustrates the point I'm making. It is my understanding that in Cuba they use aluminum bats. Is that correct? When did it start? Certainly, that might be a factor which helps hitters in Cuba.
I'm not trying to knock Cuban ball nor build it up. I'm seeking facts and to interpret those facts as accurately as possible. So far, I haven't seen anything which disproves either your contentions or Clay Davenport's about the quality of Cuban ball.
Seen on a bumper sticker: If only closed minds came with closed mouths.
Some minds are like concrete--thoroughly mixed up and permanently set.