Remove the Ctrl (move, rot, scale) transform toggle present now but leave the hand button in the header to toggle manipulators on and off. Remove the move, rotate and scale buttons. They wouldn't be needed by using the following transform widget.
I saw this combo manipulator pictured in the wiki but not used in a build.

It's nice because the different handles are spaced enough (almost, perhaps a user pref to adjust the spacing?) to grab without grabbing the wrong one, plus the sphere at the axes intersection isn't present so it doesn't interfere with selections or seeing what's selected. It shoudl also be a 2D helper, not a 3D shaded object. You would use them by click-dragging on the handles and releasing to confirm a transform. This would probably be preferred by people who like manipulators since that's how most of them function. Retaining the method "hotkey to enter transform mode, move mouse, click to confirm" is better left to the mode with manipulators turned off. Switching between local/global axes, could be Shift+MMB (or one universal hotkey) for both maniuplator mode and hotkey mode. Hold Ctrl when clicking an axes handle to constrain to planar movement, as it is now.
To retain the old transform, the G, S, R hotkeys would still function and the MMB axis toggle would work the same. Press Shift+MMB to switch between local/global axes. The Ctrl + axis key would still lock to planar constraints.
I think that instead of making the manipulators have multiple modes requiring multiple hotkeys or a mode toggle, create a switch for global/local transform so the old transform doesn't change and use a multi-functional widget for manipulator transforms.
I hope that I explained that clearly enough without any missed points or contradictions.