Why have Top11 made it impossible to win 2 games in a day

[t11_fan]

be very active in the transfer market, root out the 'bad' players in your squad and replace them early in the season when they show signs of tanking

That is worst option. Players need time to adapt on squad and tactic/formation. Constantly changing players is not road to success.

and with the necessity to rotate players with two games a day you will undoubtedly end up playing a few players who are having a 'bad' season

Rotating squad gives another opportunity - saving green points. So you can use that green points to keep good-form players in 1st squad for 2+ matches per day. Use one with weaker form as a reserve, give him opportunity to prove himself against low position teams.
I have 22 players every season, I rotate them every day. Every player needs in to learn how and when to use his main and reserve forces, that is what you learn from experience...