Short version comment: The better the catch, the more time you have for a smooth exit. Crappy catch= power comes in late and the exit is also late, and abrupt.
Long version comment:
If you adjust the stroke by raising arms higher you're going to need to lengthen the paddle, otherwise your catch will be shortened and during power phase you will lose proper blade angle relative to the water earlier. Meaning, as you pull past the paddle, the angle of the blade goes past vertical and the forward vector is lessened, you wind up pulling the boat down instead of forward.
The reason (i think) the exit is not intuitive is because while it FEELS like you're pulling hard near the end of the stroke, you're actually not doing much forward work, because of the issues with maintaining a positive blade angle discussed above. Therefore self-feedback based on feel is not helpful. Less skilled paddlers have a harder time establishing good grip/ anchor on the water up front, so you tend to wait till later in the stroke to apply the force where it is not as effective moving the boat.
This is why coaches emphasize working to feel that heavy load connecting your paddle to your feet promptly on the catch, with the blade in front of the feet. If you get a good amount of work done right up front, you have the rest of the power phase to transition to exit and it won't feel as abrupt. But the key is feeling like you're pulling a load of bricks immediately on the catch. Feels crappy at first but that's how you know you're doing it right. Zsolt calls this the "Zsolt Jolt" and Ivan Lawler says you need to "love the load". His masterclass video is worth a look if you haven't checked it out yet:
I believe Oscar explains the effective blade angle pretty well in his mauritius clinic :
www.youtube.com/watch?
time_continue=4&v=OLT0l2qf3AQ
Agree with your buddy's tip about the top hand near the ear, I found this helped me get a better positive blade angle on the catch.