A lot of you are assuming Bowler X or Y is the best bowler ever by a clear margin.
There is very little difference between a collection of ATG bowlers on pure bowling alone. Every time we have a thread on the greatest bowler we get Marshall, Imran, Lillee, Barnes, McGrath, Hadlee, Larwood, Murali, Warne and more named as the greatest. Granted, depending on the flavour of the month or what age group you talk to sometimes you will get a consensus, but the difference is minimal. There is no Bradman of bowlers.
Most of us agree averages don't tell the entire story when it comes to batsmen. Many (actually probably most) for example rate Viv higher than Kallis despite Kallis having the superior average. I don't want to get into a Viv v Kallis debate here, I just pulled those names from the top of my head. My point is the small differences in career records, or who was faster, or who had the biggest outswinger mean very little because results wise the top echelon of bowlers are pretty much equal. I think Glenn McGrath is the best specialist bowler of all time but I could argue for days with someone who believes Marshall, Hadlee or Murali is and neither of us would ever be proven right. Find me a thread where someone won one of those arguments and I'll show you Sledger is a decent human being. Those bowlers did everything everywhere (cue Lillee-in-subcontinent argument...).
So say you pick McGrath because you think he is the best bowler, but you can't conclusively prove it, and in doing so you exclude a bowler who could also make a case for being the best but who is definitely superior with the bat. In my opinion you made the wrong call. If you have players of equal ability with equal records in one field then you choose the best in the others. Even if we're not selecting for PEWS' theoretical level above test cricket where you can't assume the other team doesn't have their own Bradman, or the bowling version of him, plus they have their own selection of all time greats, I would still argue for just a fun paper exercise ATG bowlers who can bat or field are more valuable and make the team better than ATG bowlers who can't.
I do the same thing with batsmen, hence Sobers, Kallis and Hammond all make my team.