jammerculture
Prince
On the other hand +stability isn't necessary in all situations, nor do you necessarily have a lot of it from religions, as you do not get penalties from conquering, only by non state religions spreading. You can also mitigate that issue by not opening borders with known converters, like Byzantium, or with good logistics by building missionaries at the same time you build settlers to ensure that non state religions do not spread to new cities. Admittedly not necessarily possible for some countries like England that need to expand real fast.
And + 25% to building construction speed is often superior to +10% science, depending on city development, as + hammers easily translate to + science, or +$ or eventually + units depending on what you need.
Ok, but to me the question is, is the game too hard because of the religion stability? I would argue no, and point people towards the domination thread for proof. So what we are talking about is realism, and realism that destroys balance is not good. In my games I often have -30 to -50 stability in religion late game, and lets say I am around 0 overall as I've done alot of conquering, some razing and have two or three anarchies. At this point I am having to make decisions based on stability and play the game accordingly. Being able to erase that religion stability would be cheese, and would get rid of all the challenge.
If it aint broke, don't fix it.