I tend to agree with you that bots are not great for the game. Though, this depends on the economy that @steemmonsters wants to create. As a parallel example: Wizards of the Coast have both the Freemium Magic The Gathering Arena (MTGA) game AND the regular Magic the Gather Online game (MTGO). MTGO has player-to-player card trading and MTGA does not. If you want cards to have value (and have a p2p market) then it has to be extremely difficult to free-farm valuable cards. In MTGA, it's freemium, so having players farm up cards or pay to skip farming is okay.
There are mixed models, as in, it's possible that only certain cards, generally the less powerful ones, are free-farmable but the more powerful cards are not. Steem-monsters doesn't have an obligation to preserve prices on the secondary market but people are getting better at sniffing out a borked economic model -> though it remains to be seen if that is suffient to override addictive tendancies.
To your question; massively restriciting the farming ability and limiting the number of ranked games that can be played in a time period is a good solution. You propose limiting the number of games that can be played in a day. Fair, I guess. Another way would be to sell event tickets (MTGO does this) to ranked games and these form the prize pool for the game from which the house takes their cut.
The other way is to up the complexity of actually playing the game so that it's much more difficult to write a play-bot. When I tried the beta a few weeks back you made a deck and that was it. That's easy to bot. If your bot actually has to make impactful play decisions then that's much harder to bot.