It really all depends on what you do with your drones.
If you do commercial work using your
I2/X7, and use a second drone as a backup on those shoots, then there are tradeoffs between using the I1 vs the M2P for that purpose. Key issues are image quality (X5R +), flight time (M2P+), flight automation (M2P+), portability (M2P++), professional impression (I1+). Even though the M2P wins on most of those factors, my jobs hinge primarily on image quality, so I use an I1 with X5 as my backup unit on commercial shoots. You'll need to decide how important each is to you in a backup drone.
However if your reason for owning two drones is for versatility then I don't see the point of using an I1 with X5R when you also have an
I2 with X7, unless you are having operational problems with your
I2 that the latest firmware does not address (gimbal drift, battery issues, etc.). A properly functioning
I2/X7 is just an all around better rig than an I1/X5R; I can't think of any factors where the I1/X5R wins. In contrast, the MP2 does have several advantages over either inspire platform that derive from its size and design: portability, deployment speed, relative inconspicuousness, and longer flight times. I have not upgraded my original Mavic Pro for the MP2 yet, but I use the MP1 as my fun/portable drone, in context where it is not practical or worth the hassle of bringing along my
I2. If I was not out shooting for customers in demanding situations I would just own my
I2 and a Mavic. Just my 2c.