I have and do believe the lower order batting can be a factor in test cricket. I also believed that it's come to a point where it's severely over rated on this forum. It's come to a point where outside of Bradman, it's superceded and every other skill and player.
As I've mentioned previously and frequently, I believe that Sobers, Hammond and Kallis possesses the most valuable combination of skill sets in the game. You have an ATG batsman, at worst a 3rd or 4th change quality bowlers and top tier slip fielder. Two of them are totally excluded from any mentions of the greatest cricketers despite the fact that either of their skill sets have proven to be just as valuable if not more so than lower order batting and they have multiple of each. We do hear Kallis didn't bowl enough and Hammond wasn't an all rounder, what ever that means, and with no mention of their catching.
@OverratedSanity believes cordons are important but once it's to a certain standard and not below par, it's not that important and nowhere near vital enough to influence selection criteria.
@subshakerz believes that neither Hammond nor Kallis is close enough to Sachin in their primary skills for their bowling or catching to be a factor for selection or ranking. You have to be very close for it to be a tie breaker, no argument there.
Lower order batting can be crucial and be the difference in winning or losing close games, the extra runs can be useful to build decent scores to good ones.
No one's disputing that, but it's not a cheat code and it's not reliably consistent. It doesn't happen every match and hardly by the same players. There's a reason they are lower order batsmen, they aren't great or even test standard batsmen for the most part, and can sometimes build up averages in high scoring contests, while impacting the closer ones way less than would be imagined.
The same premise that
@OverratedSanity has for slip fielders I have for lower order batsmen, once they are viable lower order guys, the likes of Marshall and Warne, it's good enough.
Hadlee admittedly is a perfect medium, he's somewhere between a McGrath and Imran, undisputably a top tier pacer, likely behind only Marshall and said McGrath, but with the added batting to his repertoire. It can be argued that he is the closest to Bradman and Sobers and just a matter of preference or opinion. As bowlers, I do prefer Glenn and Malcolm as bowlers for reasons offered previously, but in the fewest words, they were consistent everywhere and were best able to take the pitch out of the equation, for me that's invaluable.
The reason I'm less willing to factor in secondary skills for bowlers are that there's only 4 of them and especially not for the opening bowlers, as it impacts more than the 6 batsmen. McGrath and Hadlee are close for me, but it's not a disservice for the latter, they're both in my top 6 and absolutely top tier ATG's. But yes, it's definely close and I wouldn't argue with anyone who believes he's more valuable than Marshall either, I would disagree, but wouldn't fight you.
The thing with secondary skills are they are depreciated, and the say way one wouldn't expect Kallis so win games with any regularity with the ball, it's equally unlikely for these guys to do so with the bat. The only secondary skills where these guys are legitimately great and at the higher end more reliable are in the slips. Now I'm not saying that any one secondary skill is more important than the next, but that's what everyone here does. The same way games have been saved by lower order batting, games have been won by 5th bowlers and just as many by great cordon play and lost by inconsistent ones. But that's largely ignored here, in fact I would place a wager that Kallis won more matches with his 5 wicket hauls than Imran did via his hundreds. Also doesn't require a deep YouTube dive to see how Smith, Kallis and deVilliers contributed to SA wins, or Lloyd, Richards and Richardson or Taylor, Waugh and Warne / Ponting did for theirs, and we can keep going...
But why do we only focus on the bowling guys, why do we say Hammond or Kallis isn't close enough to Sachin to be rated higher, but Imran close enough to McGrath? Kallis and Hammond brings two additional, and equally important and more reliable skills. As good as Imran was with the bat, Kallis and Hammond were better in the cordon and equally reliable as 5th bowlers. We just rated Hammond 10th, and Imran 8th, what's the difference? Hammond's true average is in the 60's as his post war exploits shouldn't factor into his legacy.
I'll say this, ideally a team should have a good 5th bowler, a great cordon and good no. 8 bat, but we've decided that only one is important and worthy of sacrificing the primary skill to fit it. Especially since you wouldn't chose a batsman averaging 30 to win or save you tests, but somehow believe a bowler averaging that will regularly. Yes it's a bonus, but not to the extent that we believe, and definely not worth giving up bowling prowess to achieve.