As theoretically the fitter team we should be dominating the ruck turning the player on his back and getting him facing his own line, that earns you the right to have slightly longer on in the tackle. If the tackled player is on his front and facing the right way as then the defender has to be off pretty quick that includes getting hands off the ball, that's where we get caught out when we try to slow it down because we have not won the ruck, referees recognise that and penalise accordingly. So it's not the standard of the ref it's poor technique from the players.
By all means first second set in a game test the ref out see what you can get away with, but after that a team should have it worked out.

Refs look at tackles and the move call is adjusted accordingly, defender controlling the ruck will result in slower ptb and more time to set the defence, attacker dominating as in landing on elbows and knees and still going fed defenders have to be off quick.
Defenders can only work the ball carrier on the ground in a surrender or dominant tackle.
Personally what I have seen so far we have deserved the majority of penalties

Working the tackle Mickey

It's not fitness, it's strength and technique. Our guys remain smaller, maybe more mobile but not as physical, and it's difficult to get some of the lumps into "good" positions in the tackle, in part contributing to the holding down penalties.

W q you cannot actually work the tackle once on the ground though that's the issue