With this we can see tachnically speaking, is not difficult to change any already written parameter - to change the code value of it, when talking about crypto-currencies the difficulty only comes when adding non-existant features. You can modify any of those features here
https://github.com/bitcoin/bitcoin/blob/master/src/init.cpp But you can't just alter some value in the code and get with it, consensus should be reached to modify even the minimal thing on Bitcoin as you'll modify the code in thousands or millions of user computers, it's decentralized.
Regarding your comment about consensus ... No, we can simply get rid of bitcoin, we should, it is inevitable as I am going to show ...
From the first beginning, bitcoin wasn't meant to be some 'dominant cryptocurrency' (I doubt there can be ever such a monster) it was , and it is yet, an
experiment.
Besides ordinary clueless people, two groups do not understand the word,
experiment, business men and women who hang around tech shows waiting for on opportunity to grab, and mid-level technologists who fall in love with the current state of 'any tech product that works'. These two camps are the true forces behind everything happening in the last couple of years in the bitcoin ecosystem.
And guess what? There exist no other camps! Bitcoin is overtaken, it is no more a place for any kind of improvement revolutionary or incremental, it can't be a 'decentralized cash system' and won't become anything near that, never. It is and will be digital gold, forget about money.
I mean ... are you kidding? A payment system facing a network congestion with an average of 3 transactions per second?
Yet there is a very crucial point that is exceptional about the bitcoin
experiment and its so called 'success', it deserves a credit IMO:
One should distinguish between bitcoin blockchain, the real working chain of blocks replicated thousands times around the globe and under careful maintenance of its miners, and bitcoin code base, Satoshi's legacy, although being claimed by "bitcoin core" but definitely open source and public domain. The later is the one that deserves much of the credit and has the right to live and improve, no matter which chain is using it and whether the chain operators reach consensus about its evolution or not.
What I hate about much of the altcoins is their being reckless about the Satoshi code, I prefer incremental evolution and enhancements in bitcoin (and literally any good piece of) code. So, I will soon come with a complete proposal fora brand new coin, loyal to the bitcoin code base, indifferent about the bitcoin block chain, having block time re-adjustment in its heart and ASIC resistance in its brain, both with minor improvements in the mainstream bitcoin code base.