Greetings.
I guess it's not a brand new idea, but never saw this thing being talked about.
One of the major concerns in a game is a half-bot half-human zone in lower leagues.
So i suggest a simple change:
1) improve bot teams players, not to make it a real danger, but to stop +60-80 pts wins with any lineup possible. You may take salary floor as a reference point, may be bot's payroll could be like 70% of the floor.
- bot's roster can be regenerated at the start of a season
- and if the player team goes bot, so higher league bots may be stronger
2) make bots play random tactics like they do in new testing scrimmages
Other things may be left where they are, e.g. bot's gameshape and promotion rules.
I think these changes are easy to implement.
And the profit is obvious: a little more challenge to players, even in cup games, but especially for new players.
I don't see real contras here, but you should be careful with div II bots in small countries, not to overcomplicate new players' life there.
So for me it's a reasonable upgrade with minor cost.