Firstly, there are a few things that have powers that are game breaking in the presence of other mods, and that I would personally like to be nerfed. Firstly, pistons. I find it unreasonable that a block should have the power to move or modify any other block, as this can be used for griefing and other exploits, particularly with mods that add additional blocks (I would not like to make a base out of basalt and have part of it moved, for example).
While in most cases this would be okay, it is especially blatant in this case because Mojang did not add a configuration to disable it. While Minecraft does come with a server config, this is fairly limited in uses and forces people to either play with the chance of their base being modified by a piston, or to resort to another mod to disable it. This is especially disgusting as the player SHOULD NEVER EXPLICITLY HAVE TO INSTALL ANOTHER MODIFICATION (WHICH COULD POTENTIALLY CONTAIN A VIRUS) IN ORDER TO COUNTER WHAT IS ESSENTIALLY PART OF THE FREAKING VANILLA GAME). Especially considering that the average user does not know how to install a mod and relies on a modpack to do it for them, this is quite an invasion of the end-user's rights.
Quite frankly, the person who decided to make pistons part of the default game should be shot, as it is short of MALWARE, and has no way of being disabled easily by the end user. Saying that the object in question has features that could be put to good use is an abomination of logic, as NO OBJECT THAT HAS EVEN THE SLIGHTEST POWER TO BREAK SOMEONE'S GAME SHOULD BE INCLUDED, EVEN IF IT'S BENEFITS OUTWEIGH IT'S DETRIMENTS, NO IFS OR BUTS. It is a breach of Clarification 77.1B of the United Nations Laws of Digital Rights of the User of Technology, and could possibly face up to twelve consecutive lawsuits, reaching penalties of $250,000 USD fines and up to FIVE YEARS of it's ugly vile head in prison.