Ravel’s arrangement is extremely imaginative, showing off his genius for orchestration and making explicit those things that could only be implied in the original piano work.
The brilliance, colour and imagination of the orchestration, however, obscure some of the valuable characteristics of the original.
The piano version is very virtuosic. You can see and hear the pianist struggling with some of the passages. This makes watching and listening to a performance of it a very physical, visceral experience. The seemingly effortless brilliance of the orchestral version loses this aspect.
Also, the suite was written in memory of a recently deceased friend of Mussorgsky’s, the architect Viktor Hartmann. Arguably, the personal nature of Mussorgsky's grief is expressed best through the intimate medium of the solo piano rather than the very public arena of an orchestral performance.
Sometimes clearing away the rearrangements and modifications that have been made and added to something over time can reveal original features of forgotten value.
When you next want to improve a process, or find yourself having to address a problem that has arisen in a previously trouble free area, peel back the changes that have occurred to it over time and have a good, detailed look at the original.
Have various rearrangements and modifications obscured valuable aspects? Could a refocusing of attention upon the original foundations of a tottering process help to stabilise, strengthen and even improve it?