You are right - software and training aids all help with transition. i used mockups and sims but even so there is a minimum of 5 hours for anybody to transition between analogue and glass, more normally 10 hours.
Trend information is very hard to pickup initially and even after familiar still hard to identify trends which one takes for granted with analogue instruments. There is a well known school of thought that analogue instrumentation is in fact far better at presenting data to a pilot. There is a middle ground i think as you say it is a far less cluttered setup and also a more compact scan can be done with glass.
One thing you will notice is that your brain tries to process numerical information presented by the altimeter and TAS which is not very helpful when instrument flying.