No.1
For more in-depth-game-experience i think its essential to have info whats happening during a mission, especially the reason for a failure and how it was fixed (like in the old game): for example rocket explodes, fire in capsule, craft is spinning, power loss etc. It would be also great if you would then have the opportunity to choose between abort mission,let crew/mission control fix it,continue mission (of course not when your rocket explodes, theres nothing to fix

). At the moment its just very frustrating to lose astronauts because you dont know why they had to die!
This is coming in a patch, don't worry !
For better handling it would be nice to have pictures of the employees, so you know right away who is who, just by seeing the face instead of looking up the name or the skills. It would also add some more atmosphere to the game in my opinion.
The problem is mostly about user rights. Astronauts or Cosmonauts - alive or not - don't want to have their pictures used in commercial projects, and those who accept do not give them for free. Complex topic.
3. And it would be great to add failure animation. Now is a little bit disappointing to see the normal animation and only read about failure.
The problem there is that we have come to an impressive number of different programs - and adding specific failure animations for each case of failure for each program ends with insane numbers of possiblities -, that would be probably as much work that all the animations that already exist in the game !
4. I have no clue how, but it would be better if during the animation we get more info what happened. I know everything in the Buzzopedia, but kids no read and this is the game what kids will play and learn about space science easily. I know there is a short description in the animation screen, like "TLI" and other... but I feel it needs more. And more important to explain WHY happened what happened.
Writing the Buzz-o-pedia represents a huge effort from several people including myself, and as I worked in elementary schools, I really hope (as does Buzz) that this game can contribute to get young people interested in Space Exploration, but also Sciences in general and reading, which is an essential skill to learn.

Also notice that there is a "mission steps" schema (lower left "window") that displays the spacecraft trajectory and indicates where you are currently into the mission plan.