I am not going to take a side on this debate but I stopped reading right when you made your baleroc comparison. You cannot argue a side by comparing fight mechanics and then ignoring half of such mechanics that don't favor your argument.
Yes 25 players have less room to utilize. But you are forgetting other aspects of the fight. Countdown only links 8% of your raid instead of 20% of your raid. The odds of the soaker rotation getting screwed up in 25 man are much smaller than in 10. Your odds of a healer getting torment likewise are also smaller. You also can afford a multitude of backups in 25. You also have healers doing overlapping roles, so that one misclick or bad rng will not kill a tank/dps. Healers who have had their stacks drop right as they need to drop a heal during decimation can relate to this, but this problem does not (or rarely) happen in 25. 2 healing 10 man pre-nerf (and pre-geared) was a 6 minute pure execution fight for healers where if either healer misclicked a spell or made a mistake on what they should be doing - you wiped. Healing this fight in 25 is much less stressful (yes I have done it) because you have people backing you up on your role, you will rarely get torment, and do not have to be a backup soaker in the case that all of the dps get tormented (this happens in 10 man if you use a 3 player rotation, which is generally the strongest strategy).
And before anyone tries to chime in about 3 healing 10-man, pre nerf this was not possible unless you either 1) brought the perfect raid composition and were not missing crucial buffs or 2) were fully geared in tier11 heroic gear. If your strictly 10-man, you probably don't have the option of 1, and 2 depends entirely on your progression last tier. If you walked in with ~365 on the second week of FL, you were not going to 3-heal it.