If you really want to get the best of both, then I hate to say it but a better motor controller will give you the speed you want and the low speed torque as well. A Y-Cable can be used with your receiver with something like a Sabertooth and you can have the sounds of your stock motor controller and the control of a dedicated high end controller.
I know you didn't want to upgrade your electronics yet, but keep this in mind when you do. A 3:1 can easily push one of our metal Tiger 1 tanks even at slow speeds with enough torque if the motor controller is good enough. Using a motor controller separate from your MB would allow you to tune the top speed as well (using end points on the TX) then use the stick min/max options on the MB to set the sticks. If you use the min/max option on the aftermarket MB of choice (sets the min and max travel for sticks) AFTER you set your end points on the TX to get the speed you want you can get the full range of sounds from that MB. If you set the endpoints while connected to the board or do not do the min/max stick config after you will not get the full range of sounds.
Example:
-2 cell lipo @ 8.4V is just a hair too fast for you. Set end point on tx down a bit, removed a bit of top end speed.
-Set min/max of stick travel again on MB settings (each is different)
Even though you limited the max travel on the sticks and restricted the top speed of the tank, when you do the stick config in the MB settings the stick is seen as full travel.

I like the aftermarket robotic motor controllers myself. They are super reliable and are great quality. I've used both the 2x5 and 2x12 Sabertooths and even testing another now that has even more features. I'll try to get a video soon to show how much it makes a difference, motors are nice but if you dont have the guts to push them or the resolution to get fine speed adjustments then IMO the ESC should be looked at first.