You have some good points, the mana cheat is very prevalent at the moment and it's extremely annoying but you've categorized a bit too many things together.
Cheal draw: I wouldn't consider cheap draw to be mana cheat (except Refreshing Springwater but that's different) and the fact that 8/10 classes have access to cheap draw it kinda just makes it "draw" since it's evenly spread.
Using a downside as an upside: that isn't really mana cheat, it's more of a design problem/flaw, and at the moment the most glaring problem is with Warlock and cards like Backfire being too good with the Quest but it's not really mana cheat since you're just using the drawback positively
Handbuff: you shouldn't really consider this s mana chest since yeah you may be casting an 8/8 for 2 mana, but you spent some mana to make that minion and 8/8 to begin with, it kinda circles back around.
That said I do agree that the mana cheat is a little but too present in the meta and should probably be addressed