Any Way to Zoom Magnify With Mouse?

Click Magnifier Options, then Gear icon, choose "Follow keyboard focus" and you will regain the Cntrl + or Cntrl - functions for zooming out or in:

A bit late reply but I hope it helps someone experiencing this problem.
There is an excellent utility called X-Mouse Button Control that allows you to specify all imaginable mouse mappings.

I just purchased Microsoft Bluetooth Notebook 5000 mouse in a hope that MS mouse software would allow me to remap middle wheel button and wheel up and down for mouse-based magnify zoom in and out, but no, IntelliPoint 8.2 does not even recognize this mouse as a Microsoft mouse (nor does the later Mouse and Keyboard Center from MS)!

But with X-Mouse, I can specify first that the wheel button triggers a secondary scheme ("layout 2"), where wheel up is configured to send virtual keys {LWIN}{NUM+}, and wheel down virtual keys {LWIN}{NUM-}, while the wheel button is being pressed down (even the delay can be set). Having the specification in a secondary layout retains wheel up and down doing their default operations in all other times than when the wheel button is being pressed down.

The utility also allows application specific mappings, and it is free. You just need to have a wheel button mouse, or a 4-button mouse, to achieve this functionality.

I tested this on Windows 7 Ultimate X64 and also Windows 8 Pro, with the above mentioned Microsoft mouse, and Dell Bluetooth 5 Button Travel Mini Optical Mouse.

I would not install the Intellipoint bloatware or any device's bloatware except for the driver itself, giving preference to the driver delivered by Win7 in the installer or optional Windows Updates after enabling Automatically get recommended drivers and updates for your hardware.

In Windows 8 all devices install themselves with no user participation and disallowing the device bloatware. But these improvements were developed in Win7 which is full driver-complete and should be deferred to unless problems persist or drivers go missing.

True, bloatware is a nuisance but you cannot achieve mouse-operated magnify zoom in and out with basic Win7 or 8 drivers. For me, this feature is needed for magnifying the screen in living-room context where 46-inch screen is used at 3 metre distance (bluetooth kb is readily available but only used for lengthy text inputs and otherwise kept aside and folded). Talking about bloatware, I did achieve the mentioned feature earlier on Win 7 using Logitech MX Air, but SetPoint software (which needed to be tweaked to have it perform they way I want) seems to freeze Windows 8 (the latest version they have, 6,50.152), so I had to change the mouse.

Thanks for filling us in further, Argos. It seems like you've really done your homework and testing. Your findings should help others via web searchs.