It's 2,500 miles away from Citi Field, for one. Cashman Field, their home stadium, is really out-dated too:
The other issue isn't necessarily that it's Las Vegas but that it's in the Pacific Coast League, which is an offense-heavy league, leading to bloated numbers across the board. The only slight positive is that it's not ridiculously-offensive driven like Albuquerque, Colorado Springs, and Reno are.
What nmig says...too many negatives and not nearly enough positives. Like I said earlier, I really hate the idea of Wheeler potentially pitching a full season there. But it's not like it's worth bitching over when it's set in stone that the Mets' AAA team will be there the next two seasons.
BTW DP26, just to give you an idea of what the PCL is like...it's not that uncommon for teams to finish seasons with aggregate .300 BAs. And pitching staffs to finish with ERAs over 5.00. I've gotta think that has a way of screwing with some pitchers' heads.