I actually find the "new" 109 much nicer than the "old" one: now i can actually roll and use elevators at high speeds
The heavy feeling you describe is probably due to a universal effect of the improved FM. Inertia, torque and so on are more pronounced in the new sim, especially when flying at lower airspeeds (eg, a protracted dogfight with a series of turns or even vertical maneuvers).
This heavy feeling disappears completely if you keep it going at a faster pace.