Re: BIP 100 is an unbalance. Here's why.

So what if the 8Mb pre-set limit starts to be taken advantage of? That's why pre-setting a limit so far from the original is considered radical change by many. It has never been tested in anything as large as bitcoin.

Actually it has been tested before. When 1MB blocksize limit came to effect in 2010 the average blocksize was around 0.0003 MB. So only 0.03% of available blocksize was in use. With rise to 8MB that ratio with current usage would be 5%. So situation would be relatively equal to mid 2012, when 5% of 1MB blocks were in use.

Can you give one good example how 8MB limit could be taken advantage of?

I don't think there was anyone with the interest to stress test bitcoin's transaction logs back in 2010 among the then tiny userbase. We can't be sure about what could have happened if such a stress test would be performed with a 8Mb limit.

Disagree with this, if the limit was 8 MB in June 2015 (when the spam attack happened), then it would have been alot more expensive to produce the same effect. If the attack took place in June anyway, then the motives of the attacker would be more easily discerned; miners couldn't perform the attack profitably without half full blocks to rest an attack on, which they could have given the actual blocksize we had then (and assuming they were responsible, of course).