I appreciate the civilised tone of your post so I'll respond with the respect it deserves.
On dissent, my view hasn't changed. It's nice and simple and straight forward, if you say or do anything after a decision is made then you run the risk of copping a 50 and are therefore extremely stupid.
I have no problem with the umpires paying it as they see fit. We aren't privy to what is being said on the field so we really don't know if the instances are the same or not. There'a a big difference between waving your arms and saying 'that's *smile* *smile* you stupid cheating *smile*' or waving out your arms and saying 'how was that a free kick?' for example.
To me the standard for players is very clear. Don't do or say anything after the umpire makes a decision and you don't run the risk of giving away 50. How could that be any more simple?
In terms of the rest of your post, the problem I have is like most of the criticism of umpiring, it is generalisations. 'Sometimes, consistently, rarely, all the time' are terms that always come out but they are really nothing terms without actual data and examples of these things. It's all feelings and no facts.
If sometimes means 3 times out of 10 a player is held without the ball and it isn't paid then that is 7 times out of 10 when it is paid. That's pretty good going by anyone's standards but I have a feeling people tend to remember the 3 and forget the 7.
The other thing that you mention, that is a constant, is consistency. Probably the most used term to bag umpiring.
Firstly, consistency doesn't mean errors aren't going to happen. As I've said the long term average of umpires shows the very best will go out about 8 out of 10 correct when they blow the whistle and slightly less when you factor in missed frees.
So your starting point for great umpiring is 2/3 mistakes per every 10 decisions. That's the limit of human capability. So when you say consistency we need to understand we are talking about that as a standard.
The second and most important point about consistency is it is not a consistent game to officiate. It is not tennis where the ball is either in or out. It isn't an LBW appeal where there is a set criteria to tick off in series of yes/nos to determine the correct decision.
It is a game of interpretation and definition. Prior opportunity for example is an opinion. It is a measure of time and space taken without instrumentation in a high pressure environment. Try estimating 3 seconds without using a watch and see how consistent you are and that's before you factor in doing it in the heat of a game environment. If you got within .3 of a second you'd be doing well but 2.7 - 3.3 seconds is a 20% variation already. Pretty hard to be consistent.
And based on that you can have the ball in your hands and not legally dispose of it and it is perfectly fine or you can not legally dispose of it and it is a free kick and the difference is a fraction of a second. Be consistent? Yeah right.
Then you have incidental contact. You can make high contact in a contest and it might be incidental contact or it might be a free kick. Good luck trying to be consistent with that.
Or drawing the line on how much force is used. Is the Broad one above a push in the back, or is it his momentum taking him forward? What if the contact was slightly softer? Then you have to determine if the player exaggerates.
Literally the only consistency you can ask for in those minefield is for the umpire to look at it and make a decision based on what they see each time. Of course someone else sitting watching in the stands or on TV might see it completely differently and very often they are both right. Trying umpiring a game of tennis when the same ball can be both in and out simultaneously and see how much consistency there is.
Truth is consistency is an easy whack at umpires because in AFL it is unattainable. The rule don't allow it and until we reach the point where the same robot is umpiring every single game they never will. To seek it as a fan is just condemning yourself to frustration.
It is a beautifully imperfect game with beautifully imperfect rules and the best way to enjoy it is to remember that.