As per my knowledge, there are no changes required for bitcoin as it is already proven itself in the market.
Dude people are complaining about the slow confirmation time and we need change that. I agree it has proven itself but we need certain areas to improved so that bitcoin can go further that you ever dream of. If we are struck with this issue, then bitcoin will stall. And so that there is also a high chance that it will be mass adopted sooner than later. I hope you understand why changes are needed to bitcoin technology.
If you mean with bitcoins needs be changed is bitcoins hard fork, we can take lesson from ethereum's hard fork.
The lessons and unintended results of TheDAO and the Ethereum contentious hard fork. Technical success but political failure. The expensive potential damage for all cryptocurrencies of contentious hard forks. All cryptocurrencies get one mulligan. Being in a position where you're making decisions in this ecosystem is very difficult and a dangerous handicap. Tendencies to fragment. The Bitcoin Unlimited remote exploit bug. They should be relieved it was discovered early. Quality of code does not depend on having the best "superstar" developers, because they come on a Bell curve; quality code comes from a good QA process and a very large, diverse development team matter. Ethereum has a fantastic opportunity to learn from the mistakes of Bitcoin, and Bitcoin from the mistakes of Ethereum. Cross-ecosystem learning is how we mature.