The original Mavic Pro was ground breaking when it came out.
They made subtle improvements over the first year or so, then introduced platinum version with better motors and quieter props.
It is still a good buy, batteries and other accessories are cheaper than the Mavic 2,however the M2s have further significant improvements again especially the camera - which is now very much better especially for video.
You get a bit more flight time and the robustness of the radio link is that bit better too.

The Zoom variant telephoto can be very useful, the Pro has a larger sensor camera on otherwise the same machine.
Theoretically you can swap out the cameras (but they don't just plug in!)
The Pro video especially can give older computers a work out playing it - never mind editing as highest resolution uses 10bit and new coding H.265.
If you can't utilise that without spending more $ the Zoom might be the better option.

In short I'd recommend the M2 Zoom.
The M2 Pro is best if quality video and photos are the priority.
If you want good still photos, reasonable video, and ability to scout your crops and livestock original Mavic might be best.

Sidenote, they are all a load of fun and somewhat addictive - as well as useful.