You mean Watson's starts like the one he had at Adelaide? Where he and Hussey recovered very well from the shambles that was the first 13 balls, to the point where they'd put on 91 runs and recovered the innings from 2/3 to 93/3, before Watson threw away his wicket by slashing to gully and left Australia at 93/4, which is a pretty dire position.
That's precisely what I'm getting at with Watson. He scored 50 which looks good for his average, but his innings didn't really do much in terms of either rescuing the Test for Australia or even setting Australia up to potentially win it, something Watson does far too often. And Ponting and Clarke could at least point to getting absolute beauties from Anderson early on in their innings. Watson had done the hard work before throwing it away, and exposed the lower order to a ball that was barely 30 overs old.
For the reasons you are providing, I can't buy this argument at all.
Let's make one thing clear. Nobody, including yourself I believe, has a problem with what Watson is averaging as an opener. In fact, I think it would be completely unreasonable to expect him to average more than 45-50 - if he did he would be in contention as one of the best openers of
all time.
So assuming that is something we can agree on, let me try and explain why I think your point is null.
If you accept his average is fine, then what is the difference in him, for example in the Adelaide test, getting two half centuries or a 100 and 0, or 0 and 100? In terms of runs, it makes absolutely no difference, and Australia would have been in exactly the same position. You could provide all sorts of arguments like Watson getting a 100 in the first innings would demoralise the attack and allow better partnerships to form, increasing the overall amount of runs scored etc. But then I could counter that by saying, if he got a duck in the second innings the other batsman would have been exposed to a newer ball, and the momentum would shift to the English bowlers. I really don't think there is much substance to the kind of arguments above. If anything, imo scoring two 50's is probably slightly better because it means other batsmen are protected from the new ball in both innings, rather than just one if the batsman scores e.g. a 100 and 0.
Is it a coincidence that the major criticism of Watson has come at a time when the rest of the batting has largely failed? No it isn't...if other batsman actually gave him some support, I doubt anyone would even be bringing it up. It shouldn't be expected of Watson to cover for the other batsman's failures by scoring runs at a ridiculous average.