I'm not sure how much difference the one extra day will make as there are other variables such as how much the squad has been rotated during the Easter period. It's tough for all teams to play 3 games in 8 days.
I agree that it's time to go for one fixture for each team over Easter. The Easter double header is just one of those relics of a different time that persists 'cause tradition'. Maybe you'll get an exciting Easter Monday game if you're lucky, but quite often you've just got two very tired teams who can't play to their full potential. Why would anyone want to watch two tired teams? There's no reason why 'tradition' should trump common sense. It's crazy to expect athletes these days to back up and play so many matches in what is basically a little over 1 week.
Inevitably there'll be people piping up about 'the old days' and people who worked 'down pit' then played 5 games in 2 days, while walking 25 miles each day for a loaf of bread and a pint of milk. Sport has come a long way and there's literally no good reason to put players through the physical battering of 3 games in 8 days. There has been a horrendous injury list for Super League clubs already. Player welfare needs to be taken seriously and hopefully this will be the last year of the double header.
It also means that by spreading out the fixtures you can maximise TV audiences. Televise one game on Thursday night, one on Friday, one on Saturday and one on Easter Monday.