New Macbook Pro Trackpad Too Big

Maybe this:

https://support.apple.com/kb/PH25809

There's a mode that allows the built-in trackpad to be ignored when an external mouse or trackpad is connected. It's in Accessibility>Mouse & Trackpad and not under the separate Mouse or Trackpad settings in System Preferences.

I suppose everyone has a different set of requirements. I don't use my trackpad much, but when I do I like how it works. I generally rest my wrists off to the sides to avoid the trackpad. I've use other computers with smaller trackpads and I can't get used to such a tiny one any more after using one on a Mac. I leave it on because sometimes I like to use my trackpad for gestures or perhaps a tap instead of an audible mouse click. However, I've tried turning on the feature to ignore the trackpad with a mouse connected, and it does work without any special driver with my Logitech M325.

It would be nice if we could program one of the fn keys or other special function key to disable the track pad when using a mouse/for any reason. Using the same key you could also enable the track pad when not using a mouse.

In my opinion, the best solution to date involves putting your keyboard at a lower level, to raise and straighten your wrists for more ergonomic positioning.

Others have suggested covering a portion of the keypad with a number of items, but use extreme caution, because the clearance to the front of the display is very small.

I would prefer the trackpad was smaller but I have adapted to it. This is a user-to-user support forum. You may want to also make the suggestion to Apple: Feedback - MacBook Pro - Apple