These mechanical suggestions for the most part just make all characters stronger, further invalidating existing class abilities and the process of leveling up to get cooler abilities.
If you want these to be default abilities that each of these classes get at level 1, then I'd recommend a drawback to each of these to make them mechanically ~equivalent to a basic attack/cantrip. This would then add flexibility to characters without directly increasing their power. Otherwise, they should be class abilities granted at certain levels.
This one:
Fighter:
1. Add "Readiness" ability.
Explanation: Fighter takes defensive stance taking 50% less damage from all sources except "magic" damage and parrying any melee attack dealing -30% less damage to attacker. While in that stance Fighter can't attack or move. Can be activated 2 times per Short Rest.
is similar to something that *should* be in the game for ALL classes: the Dodge action. Characters spend their action to dodge, giving them advantage on Dex Saving Throws and enemies have Disadvantage to attack them until the start of the character' next turn.
