It does matter whether you call it "broken". If the behavior continues to be correct and does not break the functionality of scripts, it shouldn't be called a breaking change, period. And if it's not a breaking change, it's not a backward compatibility issue.
And to be frank, the actual number of people this is likely to affect, even aesthetically, is extremely low. You're really not going to see "hundreds of posts" about this change. The cross section of people this affects is limited to scripts that deal with a large amount of irrational numbers and display them without $rounding.
This is already unlikely: considering that mIRC already displays up to 6 decimal places, you're not going to find many scripts that are displaying all 6 decimal places of a floating point value in a polished/distributed script. You're talking about a script that currently does this:
<+RPGBot> Wizard attacks using Magic Missile and deals 64.295829 damage!
Or one that does this:
<+ElectionBot> Candidate A has won the #CHANNEL election with 64.258724% of the vote!
Or even:
<+SpeedTestBot> You downloaded 422.875 mb in 38.291758 seconds at a rate of 11.043499 mb/s.
None of these is aesthetically pleasing in the first place, and if aesthetics mattered to these scripters/users, they likely would have already changed these values to truncate floats to a reasonable precision for display purposes. To be clear, neither of the above are using a reasonable precision for display purposes (usually 1-2 decimals). You're talking about a really small subset of scripters/users that (a) care about aesthetics enough to think 7+ decimal places is too much but also (b) don't care about aesthetics enough to have $rounded to (at most) 6 decimal places. Recall that ~14 decimal precision does not mean all floats will have 14 decimals. Many still won't (though it depends on the set of numbers being used).
Will this affects at least a few scripts? Probably. Will people notice? Maybe. Will those users consider this important enough to even bother trying to fix? Perhaps. Would this create a burden for the forum? I highly doubt it.
