The high ball/cross kick for penalties inside the 22 is now becoming standard practice...

 Mike, your obsession is getting worrisome.

 
The current rules are in place ... I know ... and they are being exploited. In the end it doesn't make for a fair contest.

The penalty is advantage enough. Why push it till the try is scored?

If the attacking side was able to score the try shortly thereafter by all means. Keeping the attacking side on the front foot isn't fair ... even when they've lost the ball in a fair contest.

The defending side should be afforded the right to defend and contest for possession.

It's a stupid rule and should be done away with

 So is there any difference between a grubber or a Garry Owen apart from height ? Both can cede possession to the opposition even a long cut-out hail Mary low percentage sorta pass can hand the ball back but your wor king from the premise that if you dont obtain any advantage you get the ball back.

 
Use the advantage to your ... errr advantage.

Don't keep punishing the defending side for the attackings sides blunders.

Giving them a "do it over and hopefully we won't mess it up this time around" isn't a fair contest.

I can't say it any simpler than that.

It's all about the contest in the end.

 I agree that in some cases too much advantage is given. There should be some sort of time cap too.

 A handling advantage should be no more than change of possession.....if possession changes it's over. A penalty advantage likewise should be brief, I agree. It should be 'immediate advantage', not 'developed' advantage. Three phases at most, otherwise you revert to the penalty kick which is the correct remedy for breaking the laws.

Mozart
Still suffering from kicking mania - we have all seen this wonderful discovery of yours  ample times and have seen that it rarely produce positive results.  What it destroy is a quick tap kick once the penalty is awarded - a much more successful usage of the ball and more often resulting in tries.  It factually limits what happens next to penalty kicks at goal or corner kicks.
The problem is the kicks may have a 10% success rate if the kicker  is accurate and launch  atop class kick - while the player who follows up the kick must be better under the high ball than the opposition recipient.   Small chance of success here and a waste of time 90% of the time.
Saw it tried twice in this morning's matches and went awry both times.
So keep us entertained with repetitive jabbing about something which could be tried as a variation - generally unsuccessfully so.     

Can anybody rid me of this meddlesome poof?

No - I won't succumb to your tirades and childishness - Grow up and find a brain somewhere to use - yours is malfunctioning. 

 
And what if you mess it up within these three phases ... what if you lose the ball to the defending side, legitimately ... due to superb play on their part? Do you go back 50m and try, try again?

How many "three phase" allotments are you permitted?

Use it or lose it, I say.