The sort of attack plan routinely devised over many hours by elite teams in hard wars against other elite teams does just that. Every one of those plans assumes that every undenied defence monster will get a special and assesses how that will impact the attack, and fashions a way to counter that eventuality. That is partly why crunching all the possibilities to achieve a 100% certain attack plan takes so much time and effort and ingenuity.
I think the operative word here is 'elite' - how many 'elite' teams exist that have a) the diversity of fully ranked monsters and b) the ongoing amount of gems to devise such ingenious attack plans? half a dozen? maybe a dozen? So to keep this tiny fraction of ML players happy to tinker around avoiding specials, the entire rest of the ML community is supposed to continue to put up with this???
ML provides enough in-game earned gems to make the proper adjustments. Problem is that the vast majority prefers to save gems for idiot races and would not move a single rune if their granny's life depended on it. Monster diversity is an issue, but often rank 3 or even rank 0 monsters can be used if there is any willingness to move runes.
You are right though: there are not many teams or players who would do this. I can think of only four or five teams of which the vast majority of players would go to such lengths if the situation called for it. Does that mean the vote of the majority should rule? I do not know. Does that mean everyone should like these changes? Most certainly not!
I am quite sure however, that even many 'elite' players will like this change, since they will have far less to fear on attack. The chances of being surprised by a smart defence from a less equipped player will be pretty much 0 after this change. And for some all that counts is winning. For me, and a few others. the process in working towards victory or defeat is the most rewarding part of the game.
And sorry to say, but if your battles against evenly matched opponents last so long that half of them are decided by specials, then there is a structural problem with your attack plans. You probably know you could use safer methods to start an attack, but you are not willing to make the adjustments. Which is fine, this is the position most players take. Does not make your claim of "battles decided by luck because of specials" in any way valid though.