Dynamic income:
I disproved both your points in this very thread:
EM rushes are more popular than EM/Denial stalls, changing the reward system wouldn't change the deck-type composition in arena because it is heavily based on win-rate
And dynamic income in no way suggests that income will be noticeably increased. Dynamic income might as well decrease "auto-income"
Restricted HP and Dex:
Need is because there is no clear gap between gold and silver decks other than overcrowding in gold pushes more bad decks out of arena, while the rewards differ greatly. In addition, skill points don't restrict "player choices" at all, they expand the choices.
Sideboard:
Again, I am not a professional game designer, so I wouldn't know the exact values for an optimal, balanced sideboard. Don't vote for the implementation of the example, vote on the implementation of the concept.