Without directly answering your question, you don't seem to have the background you need to be "improving" the undergraduate experience yet, and have some work to do. I think you're right in sensing that your question is too general
Don't talk about the "difficulties in forming such a course", and spend your initial time finding out what aspects of the first year experience you're trying to fix. Is it too many students fail calculus I? Is it that students don't know calc well enough when they're done to support the engineering curriculum? Is is that too many students drop engineering as a major and go to other disciplines? Is it that attendance in the class is poor?
You might have a number of stakeholders that you need to question -- maybe students, advisors, faculty,...
You can spend an awful lot of effort revamping a curriculum that doesn't touch the real issues. You minimize wasted resources by going through the exercises of characterizing the issues, and prioritizing what problems need to be fixed.
Now, let me, as an engineering prof, try to guess about the kinds of situations that you might be trying to improve. The biggest issues I see concerning our calc sequence is that some of our first year students have plenty of on ramp issues, and might not be ready to take calculus. I think we owe these students the support that they need to thrive in our programs.
My own experience is that there isn't going to be ONE course that can address the needs of all the first year students at the same time. If I was trying to create ONE class to support all the students, it would have multiple scaffolding options that students can select, according to their needs, but students that don't have a good foundation would need to put in an awful lot of extra work, right when they're transitioning from a high school environment. Tough path, but maybe some of the newer tools available through learning management systems can be of some help (not holding my breath).
We've landed on replacing our Calc I/II sequence with a somewhat decelerated three course sequence for students we feel would benefit, based upon placement calculations from their applications packages, with many students completing the third course during the summer. This allows a fairly usual engineering sequence, though there are some issues with the timing of Physics.
This works to some extent. I always wonder if the better option would be a semester of pre-calc for students that would benefit, followed by Calc I and Calc II