Right and after that patch the game got much harder for Spies as there were other tweaks and nerfs if you recall. In any case, I enjoyed the challenge and some of the maps were balanced more on the Merc side as well. Removing all glitches from the equation, Spies were no better than Mercs overall. The game was only truly interesting when all four players were at the top of their game but when you got into one of those matches it was an experience like no other.
You can talk all you want about the game being too easy on one side or another but I don't see that as any different from nearly every team-based game ever. Some maps favor specific sides but teams working together properly (Mercs actually using their vision modes and having intersecting patrol paths, Spies staying together until they secure an area properly with gadgets and then splitting up to hit multiple terminals, etc.) will still come out with the win nearly every time. The glitches were almost all in favor of the Spies with the exception of the one where you couldn't get neck-snapped as a Merc.