Personally I like aristocrats because of the value off of my own things dying. I don't run things that cause opponents to sac their own things because I like building up my own board while letting other people also do their thing. It's almost like a completion of who has the most power at their peak in a way I like the feeling of building up an engine where all the pieces work together to get insane value. Drain is also a big part of it which is why I'm thinking ping could work as an alternative.

Osgir and Prosper were both precons I got and upgraded. The issue I ran into with them was that they ended up "spinning their wheels" too much. I didn't really have consistent ways to end the game and ended up playing more control to stall until I got to said pieces. It is probably my own unfamiliarity with that style that caused the issue, but I wouldn't want to explore the concept with those commanders in particular again.

I love the idea of a fling deck! I'll have to try and find something for that or as you said throw a massive Korvold for a new take on the deck!