Generally speaking, the cheap decks people start the game with aren't very interesting to pilot. They don't have enough removal, which is one of the primary ways players interact with their opponent's board. They definitely don't have boardwipes, which means just playing the best creature in hand each turn is usually the right play. They typically don't have much card selection. And most complexity is concentrated at higher rarities, so these decks tend to have simple cards.

That's not to say that all cheap decks are boring, or all tournament decks are interesting, but cards like, say, Duskwatch Recruiter, Dromoka's Command, or Despise, for example, just offer more choices than Craw Wurms or Grizzly Bears.

Regarding what others have said:

Damage not going on the stack was a good change IMO. Sacrificing Mogg Fanatic was always the right play; now it's less obvious. I agree with akud on detention sphere vs. O-ring.

Hexproof over Shroud was a mistake; with that said, they seem to have figured that out, and we're getting cards like Pristine Skywise or Dragonlord Ojutai instead.

I'm sad to see Protection be replaced by Indestructible. Morph/Manifest and DFCs show that they're not entirely shying away from complex mechanics.